Patent Publication Number: US-2023157785-A1

Title: Motion based dental splints

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority, as appropriate, to U.S. Ser. No. 63/010,821, titled “MOTION BASED DENTAL SPLINTS,” and filed Apr. 16, 2020, the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Understanding and recording an accurate static relationship between teeth in a patient&#39;s upper jaw and lower jaw is an important first step in the art and science of designing dental appliances or restorations and planning dental or surgical interventions that affect dental/skeletal function and aesthetics of the facial musculature system. 
     Additionally, the dynamic motion of the lower jaw and dentition interacting functionally and aesthetically is even more important in the various reconstructive domains in dentistry and medicine that require precise knowledge and locations of the musculoskeletal-dental components that define this motion. The greater accuracy of motion definition allows for more precise design of restorations (e.g., crowns, implants, full/partial prosthesis) and associated macro procedures such as orthognathic surgery, trauma reconstruction, etc. These physical components can be described in engineering terms as a kinematic linkage system incorporating the relationship of the temporomandibular joint to the dentition and soft tissue of the face. This linkage definition has only been approximated poorly by traditional articulator devices and systems in dentistry. 
     Dental appliances may be used in the treatment of various dental conditions. Examples of dental appliances include therapeutic appliances and restorative appliances (dental restorations). Non-limiting examples of therapeutic appliances include surgical splints, therapeutic splints, occlusal splints, orthodontic retainers, and orthodontic aligners. An example of a therapeutic splint is a splint for the treatment of temporomandibular joint disorders (TMD), which may be referred to as a TMD splint. Another example of a therapeutic splint is a splint for the treatment of sleep apnea, which may be referred to as a sleep apnea splint. 
     A dental restoration is a type of dental appliance that is used to restore a tooth or multiple teeth. For example, a crown is a dental restoration that is used to restore a single tooth. A bridge is another example of a dental restoration. A bridge may be used to restore one or more teeth. A denture is another example of a dental restoration. A denture can be a full or partial denture. Dentures can also be fixed or removable. An implant is yet another example of a dental restoration. Dental implants are prosthetic devices that are placed in bone tissue of a patient&#39;s jaw and used to secure other dental restorations such as implant abutments and crowns, or partial and full dentures. In some circumstances, dental restorations are used to restore functionality after a tooth is damaged. In other circumstances, dental restorations are used to aesthetically improve a patient&#39;s dentition. 
     When complex or multiple dental appliances, dental restorations, or dental therapies are applied to a patient simultaneously, errors or inaccuracies in the representation of dental motion are compounded, resulting in inadequate or suboptimal results for patients. In the worst case, inaccurate motion data can result in the complete failure of the appliances, restorations, or treatment at very high cost clinically, financially, and emotionally. 
     Jaw and facial movement may be determined by attaching a device to the patient&#39;s dentition. 
     SUMMARY 
     In general terms, this disclosure is directed to motion-based dental splints and systems for generating motion-based dental splints. In one possible configuration and by non-limiting example, a patient assembly is coupled to a patient&#39;s dentition and an imaging system captures images of the patient assembly as the patient&#39;s dentition moves. 
     One aspect is a dental splint comprising a thin-shell aligner and a contact surface. The contact surface may be formed based on motion data. In some implementations, the motion data includes relative motion data on movement of a patient&#39;s upper dentition with respect to the patient&#39;s lower dentition. The contact surface may include one or more ridges corresponding to the positions of a contact region on the opposing dentition as a jaw movement is performed. In some examples, the dental splint is used for treatment of temporomandibular joint disorder. 
     Another aspect is a method comprising: acquiring an impression of a patient&#39;s dentition; acquiring jaw motion data for the patient; generating a thin-shell appliance for the patient based on the impression; generating a contact surface based on the motion data; and joining the contact surface with the thin-shell appliance. 
     Yet another aspect is a system for forming motion-based dental splints. The system may include a dental impressioning station configured to capture an impression of a patient&#39;s dentition. The system may also include a motion capture system configured to capture motion of the patient&#39;s dentition. The system may also include a dental splint design system configured to design a motion-based dental splint using the impression of the patient&#39;s dentition and the captured motion. 
     Examples are implemented as a computer process, a computing system, or as an article of manufacture such as a device, computer program product, or computer readable medium. According to an aspect, the computer program product is a computer storage medium readable by a computer system and encoding a computer program comprising instructions for executing a computer process. 
     The details of one or more aspects are set forth in the accompanying drawings and description below. Other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that the following detailed description is explanatory only and is not restrictive of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic block diagram illustrating an example motion capture system for capturing jaw movement. 
         FIG.  2    is a block diagram of an example patient assembly of  FIG.  1   . 
         FIG.  3    is an example embodiment of the clutch of  FIG.  2   . 
         FIG.  4    is a schematic diagram of an example motion capture system of  FIG.  1    in which two screens are used. 
         FIG.  5    illustrates a top view of an embodiment of a reference structure and an embodiment of the imaging system of  FIG.  4   . 
         FIG.  6    is a perspective view of the reference structure of  FIG.  4    disposed between the screens of the imaging system of  FIG.  4   . 
         FIG.  7    is a schematic diagram of another example motion-based dental splint. 
         FIG.  8    is a schematic diagram of another example motion-based dental splint. 
         FIG.  9    is a schematic diagram of another example motion-based dental splint. 
         FIG.  10    is a schematic diagram of another example motion-based dental splint. 
         FIG.  11    is a schematic diagram of another example motion-based dental splint. 
         FIG.  12    is a schematic diagram of another example motion-based dental splint. 
         FIG.  13    is a schematic diagram of another example motion-based dental splint. 
         FIG.  14    is a schematic diagram of another example motion-based dental splint. 
         FIG.  15    is a schematic block diagram illustrating an example of a system for using jaw motion captured by the system of  FIG.  1    to fabricate a motion-based dental splint. 
         FIG.  16    is a flowchart of an example method for generating motion-based dental splints. 
         FIG.  17    illustrates an example architecture of a computing device, which can be used to implement aspects according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. 
     The present disclosure relates to a motion-based dental splint and a system for generating motion-based dental splints. For example, the motion-based dental splints may include a dentition-coupling region and a contact surface that is generated based on motion data about the patient&#39;s jaw. The motion data may be captured with a jaw movement measurement system. For example, the jaw movement measurement system may record the motion of a patient&#39;s mandible relative to the patient&#39;s maxilla. The motion data may, for example, correspond to motion while the patient&#39;s jaw performs various movements such as a protrusive jaw movement (front-to-back) or an excursive movement (side-to-side). 
     In some embodiments, the jaw movement measurement system infers the approximate location of a screw axis corresponding to the condyloid process of the temporomandibular joint of the patient. Further, the system may generate a model of a range of motion of the mandible relative to the maxilla based on the inferred location of the screw axis, the recorded motion, or both. In some implementations, the motion data may be based on actual recorded motion, a generated model of the range of motion, or both. 
     In some embodiments, the contact surface is shaped so that when the motion-based dental splint is worn, some or all of the patient&#39;s opposing dentition make contact with the contact surface throughout a range of motion. As an example, the contact surface may be shaped so that the patient&#39;s opposing cuspids (also referred to as canines) make contact with the contact surface throughout a protrusive jaw movement. As another example, the contact surface may be shaped so that the patient&#39;s opposing anterior teeth make contact with the contact surface through an excursive jaw movement. The contact surface may balance the contact force evenly across all of the teeth that are in contact, reducing stress or tension on the temporomandibular joint. 
     The dentition-coupling region is a region of the splint that is configured to couple the splint to the patient&#39;s dentition. For example, the dentition-coupling region may include a thin-shell aligner formed from an impression of the patient&#39;s dentition. The thin shell may, for example, follow the contours of at least a portion of the patient&#39;s dentition. The thin shell may extend over the height of contours of at least some of the patient&#39;s teeth so as to clasp the patient&#39;s dentition. In some embodiments, the dentition-coupling region is configured to extend over the patient&#39;s posterior teeth so as to prevent super eruption of those posterior teeth when they are held out of contact with the opposing dentition by the contact surface. 
     In embodiments, motion recorded by the jaw movement measurement system is applied to a three-dimensional digital model of at least a portion of the patient&#39;s dentition. This motion can then be used to generate the contact surface. For example, the location of desired contact points on the surface of the opposing dentition may be swept through a specific jaw movement. This path generated by sweeping the contact may define a contact region of the contact surface. Contact points on multiple teeth may be swept through the same jaw movement to define multiple contact regions of the contact surface. These contact regions may be joined together to form the contact surface. In some embodiments, the contact regions are joined by a surface that is offset back from the contact regions so as not to inadvertently interfere with the opposing dentition making contact with the contact regions when the splint is worn. 
       FIG.  1    is a schematic block diagram illustrating an example motion capture system  100  for capturing jaw movement. For example, this motion capture system  100  may capture motion data that can be used to generate motion-based dental splints. It should be understood, however, that other methods of capture motion data may be used to generate some implementations of the dental splint. 
     In this example, the motion capture system  100  includes an imaging system  102 , a patient assembly  104 , and a motion determining device  106 . Also shown in  FIG.  1    are a patient and a network. 
     In some embodiments, the imaging system  102  includes an optical sensing assembly  110  and a screen assembly  112 . The optical sensing assembly  110  may capture a plurality of images as the patient&#39;s jaw moves. For example, the optical sensing assembly  110  may include one or more cameras such as video cameras. In some embodiments, the optical sensing assembly  110  captures a plurality of images that do not necessarily include the patient assembly, but can be used to determine the position of the patient assembly  104 . For example, the patient assembly  104  may emit lights that project onto surfaces of the screen assembly  112  and the optical sensing assembly  110  may capture images of those surfaces of the screen assembly  112 . In some implementations, the optical sensing assembly  110  does not capture images but otherwise determines the position of the projected light or lights on the surfaces of the screen assembly  112 . 
     The screen assembly  112  may include one or more screens. A screen may include any type of surface upon which light may be projected. Some implementations include flat screens that have a planar surface. Some implementations may include rounded screens, having cylindrical (or partially cylindrical) surfaces. The screens may be formed from a translucent material. For example, the locations of the lights projected on the screens of the screen assembly  112  may be visible from a side of the screens opposite the patient assembly  104  (e.g., the screen assembly  112  may be positioned between the optical sensing assembly  110  and the patient assembly  104 ). 
     In addition to capturing the images, the imaging system  102  may capture or generate various information about the images. As an example, the imaging system  102  can generate timing information about the images. Although alternatives are possible, the timing information can include a timestamp for each of the images. Additionally, a frame rate (e.g., 10 frames/second, 24 frames/second, 60 frames/second) may be stored with a group of images. Other types of information that can be generated for the images includes an identifier of a camera, a position of a camera, or settings used when capturing the image. 
     The patient assembly  104  is an assembly that is configured to be secured to the patient. The patient assembly  104  or parts thereof may be worn by the patient and may move freely with the patient (i.e., at least a part of the patient assembly  104  may, when mounted to the patient, move in concert with patient head movement). In contrast, in at least some implementations, the imaging system  102  is not mounted to the patient and does not move in concert with patient head movement. 
     In some embodiments, the patient assembly  104  may include light emitters that emit a pattern of light that projects on one or more surfaces (e.g., screens of the screen assembly  112 ), which can be imaged to determine the position of the patient assembly  104 . For example, the light emitters may emit beams of substantially collimated light (e.g., laser beams) that project onto the surfaces as points. Based on the locations of these points on the surfaces, a coordinate system can be determined for the patient assembly  104 , which can then be used to determine a position and orientation of the patient assembly  104  and the patient&#39;s dentition. 
     In some embodiments, the patient assembly  104  includes separate components that are configured to be worn on the upper dentition and the lower dentition and to move independently of each other so that the motion of the lower dentition relative to the upper dentition can be determined. Examples of the patient assembly  104  are illustrated and described throughout, including in  FIG.  2   . 
     The motion determining device  106  determines the motion of the patient assembly  104  based on images captured by the imaging system  102 . In some embodiments, the motion determining device  106  includes a computing device that uses image processing techniques to determine three-dimensional coordinates of the patient assembly  104  (or portions of the patient assembly) as the patient&#39;s jaw is in different positions. For example, images captured by the optical sensing assembly  110  of screens of the screen assembly  112  may be processed to determine the positions on the screens at which light from the patient assembly is projected. These positions on the screens of the screen assembly  112  may be converted to three-dimensional coordinates with respect to the screen assembly  112 . From those three-dimensional coordinates, one or more positions and orientations of the patient assembly  104  (or components of the patient assembly  104 ) may be determined. 
     Based on the determined positions and orientations of the patient assembly  104 , some embodiments determine the relative positions and movements of the patient&#39;s upper and lower dentition. Further, some embodiments infer the location of a kinematically derived screw axis that is usable in modeling the motion of the patient&#39;s mandible (including the lower dentition) about the temporomandibular joint. Examples of the motion determining device  106  and operations it performs are illustrated and described throughout, including in  FIGS.  16 ,  17 ,  28 , and  29   . 
       FIG.  2    is a schematic block diagram of an example patient assembly  104 . In this example, the patient assembly includes a clutch  120  and a reference structure  122 . Here, the clutch  120  and the reference structure  122  are not physically connected and can move independently of one another. 
     The clutch  120  is a device that is configured to couple to a patient&#39;s dentition. For example, the clutch  120  may grip the teeth of the dentition of the patient. In some embodiments, the clutch  120  comprises a dentition coupling device  124  and a position indicator system  128 . In some embodiments, the clutch  120  is configured to couple to the lower dentition of the patient so as to move with the patient&#39;s mandible. In other embodiments, the clutch  120  may be configured to couple to the patient&#39;s upper dentition so as to move with the patient&#39;s maxilla. 
     The dentition coupling device  124  is configured to removably couple to the patient&#39;s dentition. In some embodiments, the dentition coupling device  124  rigidly couples to the patient&#39;s dentition such that while coupled, the movement of the dentition coupling device  124  relative to the patient&#39;s dentition is minimized. Various embodiments include various coupling mechanisms. 
     For example, some embodiments couple to the patient&#39;s dentition using brackets that are adhered to the patient&#39;s teeth with a dental or orthodontic adhesive. As another example, some embodiments couple to the patient&#39;s dentition using an impression material. For example, some embodiments of the dentition coupling device  124  comprise an impression tray and an impression material such as polyvinyl siloxane. To couple the dentition coupling device  124  to the patient&#39;s dentition, the impression tray is filled with impression material and then placed over the patient&#39;s dentition. As the impression material hardens, the dentition coupling device  124  couples to the patient&#39;s dentition. 
     Alternatively, some embodiments comprise a dentition coupling device  124  that is custom designed for a patient based on a three-dimensional model of the patient&#39;s dentition. For example, the dentition coupling device  124  may be formed using a rapid fabrication machine. One example of a rapid fabrication machine is a three-dimensional printer, such as the PROJET® line of printers from 3D Systems, Inc. of Rock Hill, S.C. Another example of a rapid fabrication machine is a milling device, such as a computer numerically controlled (CNC) milling device. In these embodiments, the dentition coupling device  124  may comprise various mechanical retention devices such as clasps that are configured to fit in an undercut region of the patient&#39;s dentition. 
     Embodiments of the dentition coupling device  124  may be operable to couple to the patient&#39;s dentition using a combination of one or more mechanical retention structures, adhesives, and impression materials. For example, the dentition coupling device  124  may include apertures through which a fastening device such as a temporary anchorage device may be threaded to secure the dentition coupling device  124  to the patient&#39;s dentition. For example, the temporary anchorage devices may screw into the patient&#39;s bone tissue to secure the dentition coupling device  124 . 
     In some embodiments, the dentition coupling device  124  includes one or more fiducial markers, such as hemispherical inserts, that can be used to establish a static relationship between the position of the clutch  120  and the patient&#39;s dentition. For example, the dentition coupling device  124  may include three fiducial markers disposed along its surface. The location of these fiducial markers can then be determined relative to the patient&#39;s dentition such as by capturing a physical impression of the patient with the clutch attached or using imaging techniques such as capturing a digital impression (e.g., with an intraoral scanner) or other types of images of the dentition and fiducial markers. Some embodiments of the dentition coupling device  124  do not include fiducial markers. One or more images or a digital impression of the patient&#39;s dentition captured while the dentition coupling device  124  is mounted may be aligned to one or more images or a digital impression of the patient&#39;s dentition captured while the dentition coupling device  124  is not mounted. 
     The position indicator system  128  is a system that is configured to be used to determine the position and orientation of the clutch  120 . In some embodiments, the position indicator system  128  includes multiple fiducial markers. In some examples, the fiducial markers are spheres. Spheres work well as fiducial markers because the location of the center of the sphere can be determined in an image regardless of the angle from which the image containing the sphere was captured. The multiple fiducial markers may be disposed (e.g., non-collinearly) so that by determining the locations of each (or at least three) of the fiducial markers, the position and orientation of the clutch  120  can be determined. For example, these fiducial markers may be used to determine the position of the position indicator system  128  relative to the dentition coupling device  124 , through which the position of the position indicator system  128  relative to the patient&#39;s dentition can be determined. 
     Some implementations of the position indicator system  128  do not include separate fiducial markers. In at least some of these implementations, structural aspects of the position indicator system  128  may be used to determine the position and orientation of the position indicator system  128 . For example, one or more flat surfaces, edges, or corners of the position indicator system  128  may be imaged to determine the position and orientation of the position indicator system  128 . In some implementations, an intraoral scanner is used to capture a three-dimensional model (or image) that includes a corner of the position indicator system  128  and at least part of the patient&#39;s dentition while the dentition coupling device  124  is mounted. This three-dimensional model can then be used to determine a relationship between the position indicator system  128  and the patient&#39;s dentition. The determined relationship may be a static relationship that defines the position and orientation of the position indicator system  128  relative to a three-dimensional model of the patient&#39;s dentition (e.g., based on the corner of the position indicator system  128  that was captured by the intraoral scanner). 
     In some embodiments, the position indicator system  128  includes a light source assembly that emits beams of light. The light source assembly may emit substantially collimated light beams (e.g., laser beams). In some embodiments, the light source assembly is rigidly coupled to the dentition coupling device  124  so that as the dentition coupling device  124  moves with the patient&#39;s dentition, the beams of light move. The position of the dentition coupling device  124  is then determined by capturing images of where the light beams intersect with various surfaces (e.g., translucent screens disposed around the patient). Embodiments that include a light source assembly are illustrated and described throughout. 
     The reference structure  122  is a structure that is configured to be worn by the patient so as to provide a point of reference to measure the motion of the clutch  120 . In embodiments where the clutch  120  is configured to couple to the patient&#39;s lower dentition, the reference structure  122  is configured to mount elsewhere on the patient&#39;s head so that the motion of the clutch  120  (and the patient&#39;s mandible) can be measured relative to the rest of the patient&#39;s head. For example, the reference structure  122  may be worn on the upper dentition. Beneficially, when the reference structure  122  is mounted securely to the patient&#39;s upper dentition, the position of the reference structure  122  will not be impacted by the movement of the mandible (e.g., muscle and skin movement associated with the mandibular motion will not affect the position of the reference structure  122 ). Alternatively, the reference structure  122  may be configured to be worn elsewhere on the patient&#39;s face or head. 
     In some embodiments, the reference structure  122  is similar to the clutch  120  but configured to be worn on the dental arch opposite the clutch (e.g., the upper dentition if the clutch  120  is for the lower dentition). For example, the reference structure  122  shown in  FIG.  2    includes a dentition coupling device  130  that may be similar to the dentition coupling device  124 , and a position indicator system  134  that may be similar to the position indicator system  128 . 
       FIG.  3    illustrates an embodiment of a clutch  400 . The clutch  400  is an example of the clutch  120 . In this example, the clutch  400  includes a dentition coupling device  402  and a light source assembly  404 , and an extension member  408 . The dentition coupling device  402  is an example of the dentition coupling device  124 , and the light source assembly  404  is an example of the position indicator system  128 . 
     The light source assembly  404 , which may also be referred to as a projector, is a device that emits light beams comprising light that is substantially collimated. Collimated light travels in one direction. A laser beam is an example of collimated light. In some embodiments, the light source assembly  404  includes one or more lasers. Although alternatives are possible, the one or more lasers may be semiconductor lasers such as laser diodes or solid-state lasers such as diode-pumped solid-state lasers. 
     In some embodiments, the light source assembly  404  comprises a first, second, and third light emitter. The first and second light emitters may emit substantially collimated light in parallel but opposite directions (i.e., the first and second light emitters may emit light in antiparallel directions) such as to the left and right of the patient when the clutch  400  is coupled to the patient&#39;s dentition. In some embodiments, the first and second light emitters are collinear or are substantially collinear (e.g., offset by a small amount such as less than 5 micrometers, less than 10 micrometers, less than 25 micrometers, less than 50 micrometers, or less than 100 micrometers). The third light emitter may emit substantially collimated light in a direction of a line that intersects with or substantially intersects with lines corresponding to the direction of the first and second light emitters. Lines that intersect share a common point. Lines that substantially intersect do not necessarily share a common point, but would intersect if offset by a small amount such as less than 5 micrometers, less than 10 micrometers, less than 25 micrometers, less than 50 micrometers, or less than 100 micrometers. In some embodiments, the third light emitter emits light in a direction that is perpendicular to the first and second light emitters, such as toward the direction the patient is facing. 
     In some embodiments, the third light emitter emits light in a direction that is offset from the direction of the first light emitter so as to be directed toward the same side of the patient as the direction of the first light emitter. For example, the third light emitter may be offset from the first light emitter by an offset angle of less than  90  degrees such that the light emitted by both the first light emitter and the second light emitter intersect with the same screen (e.g., a planar screen having a rectangular shape and being disposed on a side of the patient). The third light emitter may be offset from the first light emitter by an offset angle of between approximately 1 degree to 45 degrees. In some implementations, the offset angle is between 3 degrees and 30 degrees. In some implementations, the offset angle is between 5 degrees and 15 degrees. For example, the offset angle may be less than 10 degrees. 
     In some embodiments, one or more compensation factors are determined to compensate for an offset from the first and second light emitters being collinear, or an offset from the third light emitter emitting light in a direction of a line that intersects with the directions of the first and second light sources. A compensation factor may also be determined for the offset angle of the third light emitter with respect to the first and second light emitters. For example, an offset angle compensation factor may specify the angle between the direction of the third light emitter and a line defined by the first light emitter. In implementations in which the orientation of the third light emitter is directed perpendicular to or substantially perpendicular to the direction of the first light emitter, the offset angle compensation factor may be 90 degrees or approximately 90 degrees. In implementations in which the orientation of the third light emitter is directed toward a side of the patient, the offset angle compensation factor may, for example, be between approximately 5 and 45 degrees. The compensation factors may be determined specifically for each position indicator system manufactured to account for minor variation in manufacturing and assembly. The compensation factors may be stored in a datastore (such as on the motion determining device  106  or on a computer readable medium accessible by the motion determining device  106 ). Each position indicator system may be associated with a unique identifier that can be used to retrieve the associated compensation factor. The position indicator system  134  may include a label with the unique identifier or a barcode, QR code, etc. that specifies the unique identifier. 
     Some embodiments of the light source assembly  404  include a single light source and use one or more beam splitters such as prisms or reflectors such as mirrors to cause that light source to function as multiple light emitters by splitting the light emitted by that light source into multiple beams. In at least some embodiments, the emitted light emanates from a common point. As another example, some embodiments of the light source assembly  404  may comprise apertures or tubes through which light from a common source is directed. Some embodiments may include separate light sources for each of the light emitters. 
     In the example of  FIG.  3   , the light source assembly  404  includes light emitters  406   a,    406   b,  and  406   c  (referred to collectively as light emitters  406 ) and a housing  410 . The light emitter  406   a  is emitting a light beam L 1 , the light emitter  406   b  is emitting a light beam L 2 , and the light emitter  406   c  is emitting a light beam L 3 . The light beams L 1  and L 2  are parallel to each other, but directed in opposite directions. The light beam L 3  is perpendicular to the light beams L 1  and L 2 . In at least some embodiments, the housing  410  is configured to position the light emitters  406  so that the light beams L 1 , L 2 , and L 3  are approximately co-planar with the occlusal plane of the patient&#39;s dentition. Although the light beam L 3  is perpendicular to the light beams L 1  and L 2  in the example of  FIG.  3   , alternatives are illustrated and described with respect to at least  FIGS.  22 - 28   . 
     The housing  410  may be approximately cube shaped and includes apertures through which the light emitters  406  extend. In other embodiments, the light emitters do not extend through apertures in the housing  410  and instead light emitted by the light emitters  406  passes through apertures in the housing  410 . 
     In the example of  FIG.  3   , the dentition coupling device  402  is rigidly coupled to the light source assembly  404  by an extension member  408 . The extension member  408  extends from the dentition coupling device  402  and is configured to extend out of the patient&#39;s mouth when the dentition coupling device  402  is worn on the patient&#39;s dentition. In some embodiments, the extension member  408  is configured so as to be permanently attached to the light source assembly  404  such as by being formed integrally with the housing  410  or joined via welding or a permanent adhesive. In other embodiments, the extension member  408  is configured to removably attach to the light source assembly  404 . Because the light source assembly  404  is rigidly coupled to the dentition coupling device  402 , the position and orientation of the dentition coupling device  402  can be determined from the position and orientation of the light source assembly  404 . 
     In some embodiments, the housing  410  and the dentition coupling device  402  are integral (e.g., are formed from a single material or are coupled together in a manner that is not configured to be separated by a user). In some embodiments, the housing  410  includes a coupling structure configured to removably couple to the extension member  408  of the dentition coupling device  402 . In this manner, the dentition coupling device  402  can be a disposable component that may be custom fabricated for each patient, while the light source assembly  404  may be reused with multiple dentition coupling devices. In some embodiments, the housing  410  includes a connector that is configured to mate with a connector on the dentition coupling device  402 . Additionally, the housing  410  may couple to the dentition coupling device  402  with a magnetic clasp. Some embodiments include a registration structure that is configured to cause the housing  410  to join with the dentition coupling device  402  in a repeatable arrangement and orientation. In some embodiments, the registration structure comprises a plurality of pins and corresponding receivers. In an example, the registration structure includes a plurality of pins disposed on the housing  410  and corresponding receivers (e.g., holes) in the dentition coupling device  402  (or vice versa). In some embodiments, the registration structure comprises a plurality of spherical attachments and a plurality of grooves. In one example, the registration structure includes three or more spherical attachments disposed on the housing  410  and two or more v-shaped grooves disposed on the dentition coupling device  402  that are disposed such that the spherical attachments will only fit into the grooves when the housing  410  is in a specific orientation and position relative to the dentition coupling device  402 . In some implementations, the registration structure includes a spring-mounted pin or screw that serves as a detent to impede movement of the housing  410  with respect to the dentition coupling device  402 . 
       FIG.  4    illustrates an implementation of a motion capture system  1100  for capturing jaw movement in which only two screens are used. The motion capture system  1100  is an example of the system  100 . The motion capture system  1100  includes an imaging system  1102  and a patient assembly  1104 . In this example, the imaging system  1102  includes a housing  1110 . The imaging system also includes screen  1138   a  and a screen  1138   b  (collectively referred to as screens  1138 ), which are positioned so as to be on opposite sides of the patient&#39;s face (e.g., screen  1138   b  to the left of the patient&#39;s face and screen  1138   a  to the right of the patient&#39;s face). In some implementations, a screen framework is disposed within the housing  1110  to position the screens  1138  with respect to each other and the housing  1110 . 
     As can be seen in  FIG.  4   , this implementation does not include a screen disposed in front of the patient&#39;s face. Beneficially, by not having a screen in front of a patient&#39;s face, the system  1100  which may allow better access to the patient&#39;s face by a caregiver. Also shown, is patient assembly  1104  of the motion capture system  1100 . 
     In at least some implementations, the patient assembly  1104  includes a clutch  1120  and a reference structure  1122 , each of which include a light source assembly having three light emitters. The clutch  1120  is an example of the clutch  120  and the reference structure  1122  is an example of the reference structure  122 . In  FIG.  4   , the clutch  1120  is attached to the patient&#39;s mandible (i.e., lower dentition) and is emitting light beams L 1 , L 2 , and L 3 . Light beams L 1  and L 3  are directed toward the screen  1138   a,  intersecting at intersection points I 1  and I 3 , respectively. Light beam L 2  is directed toward the screen  1138   b.  Although alternatives are possible, in this example, the light beams L 1  and L 3  are offset from each other by approximately 15 degrees. The light beams L 1  and L 2  are collinear and directed in opposite directions (i.e., L 2  is offset from L1 by 180 degrees). 
     The reference structure  1122  is attached to the patient&#39;s maxilla (i.e., upper dentition) and is emitting light beams L 4 , L 5 , and L 6 . Light beams L 4  and L 6  are directed toward the screen  1138   b.  Light beam L 5  is directed toward the screen  1138   a , intersecting at intersection point I 5 . Although alternatives are possible, in this example, the light beams L 4  and L 6  are offset from each other by approximately 15 degrees. The light beams L 4  and L 5  are collinear and directed in opposite directions (i.e., L 4  is offset from L 5  by 180 degrees). 
     As the patient&#39;s dentition moves around, the clutch  1120  and the reference structure  1122  will move in concert with the patient&#39;s dentition, causing the lights beams to move and the intersection points to change. An optical sensing assembly of the motion capture system  1100  (e.g., cameras embedded within the housing  1110  of the system  1100  behind the screens  1138   a  and  1138   b ) may capture images of the screens  1138  so that the intersection points can be determined. The location of a first axis associated with the clutch  1120  may be identified based on the intersection points from the light beams L 1  and L 2 . An intersection coordinate between the light beams L 1  and L 3  may then be determined based on the distance between the intersection points I 1  and I 3  on the screen  1138   a.  For example, the distance from the intersection point I 1  along the first axis can be determined based on the distance between the points I 1  and I 3  and the angle between I 1  and I 3 . As described in more detail elsewhere herein, the angle between I 1  and I 3  is determined for the clutch  1120  and may be stored in a data store, for example, on a non-transitory computer-readable storage medium. Using this distance, the intersection coordinate can be found, which will have a known relationship to the clutch  1120  and therefore the patient&#39;s dentition. A coordinate system for the clutch  1120  can be determined based on the intersection points too (e.g., a second axis is defined by the cross product of the first axis and a vector between the intersection points I 1  and I 3 , and a third axis is defined by the cross product of the first axis and the second axis). In a similar manner, the position and orientation of the reference structure  1122  can be determined based on the intersection points of the light beams L 4 , L 5 , and L 6  with the screens  1138   a  and  1138   b.    
     In some implementations, three-dimensional coordinate systems for the clutch and the reference structure are determined using only two screens. In some implementations, the motion capture system includes only two screens and the motion capture system does not include a third screen. In some implementations, the imaging system captures images of only two screens. Some implementations identify intersection points using images captured of only two screens. For example, two intersection points from light beams emitted by a reference structure are identified on an image of the same screen. 
     In some implementations, a light emitter being oriented to emit light in a first direction toward the screen means the light emitter is oriented to emit light in a first direction toward the screen when the light emitter is attached to a patient (or other structure) and positioned for motion tracking with respect to the imaging system. 
       FIG.  5    illustrates a top view of an embodiment of a reference structure  1430  and an embodiment of an imaging system  1432 . The reference structure  1430  is an example of the reference structure  1122 . The imaging system  1432  is an example of the imaging system  1102 . 
     The reference structure  1430  includes a dentition coupling device  1434 , an extension member  1440 , and a light source assembly  1442 . The dentition coupling device  1434  is an example of the dentition coupling device  130  and may be similar to the example dentition coupling devices previously described with respect to embodiments of the clutch. The light source assembly  1442  is an example of the position indicator system  134 . In this example, the light source assembly  1442  includes light emitters  1450   a,    1450   b,  and  1450   c  (collectively referred to as light emitters  1450 ). 
     The dentition coupling device  1434  is configured to removably couple to the dentition of the patient. The dentition coupling device  1434  is coupled to the opposite arch of the patient&#39;s dentition as a clutch (e.g., the dentition coupling device  1434  couples to the maxillary arch when the clutch is coupled to the mandibular arch). In some embodiments, the dentition coupling device  1434  is coupled to the extension member  1440  that is configured to extend out through the patient&#39;s mouth when the dentition coupling device  1434  is coupled to the patient&#39;s dentition. The extension member  1440  may be similar to the extension member  408 . 
     The imaging system  1432  includes screens  1438   a  and  1438   b  (referred to collectively as screens  1438 ), and cameras  1420   a  and  1420   b  (referred to collectively as cameras  1420 ). In this example, the screen  1438   a  is oriented parallel to the screen  1438   b.  In some embodiments. The imaging system  1432  may also include a screen framework (not shown) that positions the screens  1438  with respect to each other. For example, the screen framework may extend beneath the reference structure  1430  and couple to the bottoms of the screens  1438 . Together, the screens  1438  and the screen framework are an example of the screen assembly  112 . The cameras  1420  are an example of the optical sensing assembly  110 . 
     The screens  1438  may be formed from a translucent material so that the points where the light beams emitted by the light source assembly  1442  intersect with the screens  1438  may be viewed from outside of the screens  1438 . Images that include these points of intersection may be recorded by the cameras  1420 . The motion determining device  106  may then analyze these captured images to determine the points of intersection of the light beams with the screens  1438  to determine the location of the light source assembly  1442 . The position of the light source assembly of a clutch (not shown) may be determined in a similar manner. 
     The cameras  1420  are positioned and oriented to capture images of the screens  1438 . For example, the camera  1420   a  is positioned and oriented to capture images of the screen  1438   a,  and the camera  1420   b  is positioned and oriented to capture images of the screen  1438   b.  In some embodiments, the cameras  1420  are mounted to the screen framework so that they are position and orientation of the cameras  1420  are fixed with respect to the screens. For example, each of the cameras  1420  may be coupled to the screen framework by a camera mounting assembly such as is shown in  FIG.  10   . In this manner, the position and orientation of the cameras  1420  relative to the screens  1438  does not change if the screen framework is moved. In some implementations, the screen framework includes a housing (e.g., as shown at  1110  in  FIG.  4   ), within which the cameras  1420  are disposed. 
       FIG.  6    illustrates a perspective view of the reference structure  1430  disposed between the screens  1438  of the imaging system  1432 . The screens  1438  are joined together by a screen framework  1436  that positions and orients the screens  1438  with respect to one another. In this example, the light emitter  1450   a  is emitting a light beam L 4 , which intersects with the screen  1438   b  at intersection point I 4 ; the light emitter  1450   b  is emitting a light beam L 5 , which intersects with the screen  1438   a  at intersection point I 5 ; and the light emitter  1450   c  is emitting a light beam L 6 , which intersects with the screen  1438   a  at intersection point I 6 . As the position and orientation of the reference structure  1430  change relative to the screens  1438 , the locations of at least some of the intersection points I 4 , I 5 , and I 6  will change as well. 
     The camera  1420   a  captures images of the screen  1438   a,  including the intersection point I 5  of the light beam L 5  emitted by the light emitter  1450   b.  The camera  1420   a  may capture a video stream of these images. Similarly, although not shown in this illustration, the cameras  1420   b  captures images of the screens  1438   b  and the intersection points I 4  and I 6 . 
     The captured images from the cameras  1420  are then transmitted to the motion determining device  106 . The motion determining device  106  may determine the location of the intersection points I 4 , I 5 , and I 6 , and from those points the location of the light source assembly  1442 . In some embodiments, a point of common intersection for the light beams L 4 , L 5 , and L 6  is determined based on the location of the intersection points I 4 , I 5 , and I 6  (e.g., the point at which the light beams intersect or would intersect if extended). Based on the determined locations of the light beams, the location and orientation of the reference structure  1430  relative to the screens  1438  can be determined. 
       FIG.  7    is a schematic diagram of a motion-based dental splint  700  that includes a thin-shell aligner  702  and a contact surface  704 . The thin-shell aligner  702  may, for example, have an interior surface and exterior surface. The interior surface may follow the contours of at least a portion of the patient&#39;s dentition. At least a portion of the exterior surface may also follow (or be based on) the contours of the patient&#39;s dentition. For example, the thin-shell aligner  702  may have a thickness of approximately 0.1-1 millimeters separating the interior surface from the exterior surface. In some implementations, the thin-shell aligner has a thickness of 0.5 millimeters. The exterior surface and the interior surface may be joined. For example, the exterior surface and the interior surface may be joined by an edge surface. 
     The interior surface may be an offset surface formed by offsetting the contours of the patient&#39;s dentition. The exterior surface may be an offset surface formed by offsetting the interior surface. 
     The contact surface  704  may be a part of the exterior surface of the thin-shell aligner  702 . For example, the exterior surface may include the contact surface and a contour-following surface. The contour-following surface may represent the portion of the exterior surface other than the contact surface  704 . The contour following surface of the exterior surface may be an offset surface formed by offsetting the interior surface. At the contact surface  704 , the thin-shell aligner  702  may be thicker than in the contour-following region. 
     In this example, the contact surface  704  extends from cuspid to cuspid. The contact surface  704  may have a concave shape in the cross-arch dimension (direction). As used herein, the cross-arch dimension (direction) refers to a direction that is perpendicular or approximately perpendicular to the dental arch. For example, the cross-arch dimension (direction) corresponds approximately to the labial-lingual dimension of the anterior teeth and the buccal-lingual dimension of posterior teeth. An example of the arch and cross-arch dimension (direction) are shown in  FIG.  7    for illustrative purposes. 
     This concave shape may be defined based on the motion-data. In some embodiments, the contact surface  704  may be raised in the incisal (anterior) region and may slope away toward the posterior. 
       FIG.  8    is a schematic diagram of a motion-based dental splint  710  that includes the thin-shell aligner  702  and a contact surface  714 . In this example, the contact surface  714  is similar to the contact surface  704  and extends from cuspid to cuspid. The contact surface  714  includes contact ridges  716   a  and  716   b  (referred to collectively as contact ridges  716 ). The contact ridges  716  may be formed by moving contact regions on the cuspids opposing the splint through an excursive movement based on motion data. 
       FIG.  9    is a schematic diagram of a motion-based dental splint  720  that includes the thin-shell aligner  702  and contact surfaces  724   a  and  724   b  (referred to collectively as contact surface  724 ). In this example, the contact surfaces  724   a  and  724   b  each cover a cuspid. The contact surface  724  may have a concave shape in the cross-arch dimension. The contact surface  724   a  includes a contact ridge  726   a  and the contact surface  724   b  includes a contact ridge  726   b.  The contact ridges  726   a  and  726   b  may be formed by moving contact regions on the cuspids opposing the splint through a protrusive movement based on motion data. 
       FIG.  10    is a schematic diagram of a motion-based dental splint  730  that includes the thin-shell aligner  702  and the contact ridges  726   a  and  726   b.  In this example, the contact ridges  726   a  and  726   b  are joined directly to the thin-shell aligner  702 . 
       FIG.  11    is a schematic diagram of a motion-based dental splint  740  that includes the thin-shell aligner  702  and a contact surface  744 . In this example, the contact surface  744  is similar to the contact surface  704  and extends from cuspid to cuspid. The contact surface  744  includes contact ridges  746   a,    746   b,    746   c,    746   d,    746   e , and  746   f  (referred to collectively as contact ridges  746 ). The contact ridges  746  may be formed by moving contact regions on the anterior teeth opposing the splint through an excursive movement based on motion data. 
       FIG.  12    is a schematic diagram of a motion-based dental splint  750  that includes the thin-shell aligner  702  and a contact surface  754 . In this example, the contact surface  754  is similar to the contact surface  704  and extends from cuspid to cuspid. The contact surface  754  includes contact ridges  756   a,    756   b,    756   c,    756   d,    756   e , and  756   f  (referred to collectively as contact ridges  756 ). The contact ridges  756  may be formed by moving contact regions on the anterior teeth opposing the splint through various jaw movements based on motion data. In this example, the contact ridges  756   a  and  756   f  are formed by moving contact regions on the cuspids opposing the splint through both excursive and protrusive movements based on motion data, and the contact ridges  756   b,    756   c,    756   d,  and  756   e  are formed by moving contact regions on the incisors opposing the splint through excursive movements based on motion data. 
       FIG.  13    is a schematic diagram of a motion-based dental splint  760  that includes the thin-shell aligner  702  and a contact surface  764 . In this example, the contact surface  764  is similar to the contact surface  744  and extends from cuspid to cuspid. The contact surface  764  includes contact ridges  766   a,    766   b,    766   c,    766   d,    766   e , and  766   f  (referred to collectively as contact ridges  766 ). The contact ridges  766  may be formed by moving contact regions on the anterior teeth opposing the splint through an excursive movement based on motion data. In this example, the contact ridges  766   a  and  766   f  may be similar to or identical to the contact ridges  746   a  and  746   f , respectively, shown in  FIG.  11   . The contact ridges  766   b,    766   c,    766   d,  and  766   e  may be similar to the contact ridges  746   b,    746   c,    746   d,  and  746   e,  respectively, except that the contact ridges  766   b,    766   c,    766   d,  and  766   e  may be longer as they include extreme lateral regions that are labeled XL in this figure. The extreme lateral regions (which may also be referred to as cross-over regions) may extend on one or both sides of the contact ridges. The extreme lateral regions may be positioned to contact some or all of the patient&#39;s teeth when the patient&#39;s teeth move from a standard bite to a cross-bite (e.g., the lingual cusps of the patient&#39;s upper molars cross-over the buccal cusps of the corresponding lower teeth). Here, the extreme lateral regions are shown for the patient&#39;s anterior teeth but not for the patient&#39;s cuspids as the patient&#39;s cuspids may be out of contact during extreme lateral movement. In some embodiments, the contact surface  764  may include regions for the incisors to nest in during cross-over motions that are designed based on motion data. 
       FIG.  14    is a schematic diagram of a side view of a dental splint arrangement  780  that includes a dental splints  781   a  and  781   b  and joining structure  786 . The dental splint  780   a  includes a thin-shell aligner  782   a  and an attachment structure  784   a.  The dental splint  780   b  includes a thin-shell aligner  782   b  and an attachment structure  784   b.  Although not shown, at least one of the dental splints  780   a  and  780   b  may also include a contact surface similar to the contact surfaces illustrated and described with respect to at least one of  FIGS.  7 - 13   . The joining structure  786  joins the dental splints  781   a  and  781   b.  The joining structure  786  may provide a spring-like force to pull the dental splint  781   b  forward with respect to the dental splint  781   a.  Examples of the joining structure  786  include elastic bands and springs. The joining structure  786  may attach to the attachment structure  784   a  and the attachment structure  784   b.  Examples of the attachment structures  784   a  and  784   b  include ridges, buttons, and hooks upon which ends for the structure  786  can be secured. 
       FIG.  15    is a schematic block diagram illustrating an example of a system  800  for using jaw motion captured by the motion capture system  100  to fabricate a motion-based dental splint  824  or provide dental therapy. In this example, the system  800  includes a dental office  802  and a dental lab  804 . 
     The example dental office  802  includes a dental impression station  806 , the motion capture system  100 , and a dental therapy station  826 . Although shown as a single dental office in this figure, in some embodiments, the dental office  802  includes multiple dental offices. For example, in some embodiments, one or both of the dental impression station  806  and the motion capture system  100  are in a different dental office than the dental therapy station  826 . Further, in some embodiments, one or more of the dental impression station  806 , the motion capture system  100 , and the dental therapy station  826  are not in a dental office. 
     The example dental impression station  806  generates a dental impression  808  of the dentition of the patient. The dental impression  808  is a geometric representation of the dentition of the patient. In some embodiments, the dental impression  808  is a physical impression captured using an impression material, such as sodium alginate, or polyvinylsiloxane. In other embodiments, other impression materials are used as well. In some embodiments, the dental impression is captured by an impression device of the motion capture system  100 . In other words, some embodiments do not include a dental impression station  806  that is separate from the motion capture system  100 . 
     In some embodiments, the dental impression  808  is a digital impression. In some embodiments, the digital impression is represented by one or more of a point cloud, a polygonal mesh, a parametric model, or voxel data. In some embodiments, the digital impression is generated directly from the dentition of the patient, using for example an intraoral scanner. Example intraoral scanners include the TRIOS Intra Oral Digital Scanner, the Lava Chairside Oral Scanner C.O.S., the Cadent iTero, the Cerec AC, the Cyrtina IntraOral Scanner, and the Lythos Digital Impression System from Ormco. In other embodiments, a digital impression is captured using other imaging technologies, such as computed tomography (CT), including cone beam computed tomography (CBCT), ultrasound, and magnetic resonance imaging (MRI). In yet other embodiments, the digital impression is generated from a physical impression by scanning the impression or plaster model of the dentition of the patient created from the physical impression. Examples of technologies for scanning a physical impression or model include three-dimensional laser scanners and computed tomography (CT) scanners. In yet other embodiments, digital impressions are created using other technologies. 
     The motion capture system  100  has been described previously and captures a representation of the movement of the dental arches relative to each other. In some embodiments, the motion capture system  100  generates motion data  810  representing the movement of the arches relative to one another. In some embodiments, the motion capture system  100  generates the motion data  810  from optical measurements of the dental arches that are captured while the dentition of the patient is moved. In some embodiments, the optical measurements are extracted from images or video data recorded while the dentition of the patient is moved. Additionally, in some embodiments, the optical measurements are captured indirectly. For example, in some embodiments, the optical measurements are extracted from images or video data of one or more devices (e.g., the patient assembly  104 ) that are secured to a portion of the dentition of the patient. In other embodiments, the motion data  810  is generated using other processes. Further, in some embodiments, the motion data  810  includes transformation matrices that represent the position and orientation of the dental arches. The motion data  810  may include a series of transformation matrices that represent various motions or functional paths of movement for the patient&#39;s dentition. Other embodiments of the motion data  810  are possible as well. 
     In some embodiments, still images are captured of the patient&#39;s dentition while the dentition of the patient is positioned in a plurality of bite locations. In some embodiments, image processing techniques are used to determine the positions of the patient&#39;s upper and lower arches relative to each other (either directly or based on the positions of the attached patient assembly  104 ). In some embodiments, the motion data  810  is generated by interpolating between the positions of the upper and lower arches determined from at least some of the captured images. 
     The motion data  810  may be captured with the patient&#39;s jaw in various static positions or moving through various motions. For example, the motion data  810  may include a static measurement representing a centric occlusion (i.e., the patient&#39;s mandible closed with teeth fully engaged) or centric relation (i.e., the patient&#39;s mandible nearly closed, just before any shift occurs that is induced by tooth engagement or contact) bite of a patient. The motion data  810  may also include static measurements or sequences of data corresponding to protrusive (i.e., the patient&#39;s mandible being shifted forward while closed), lateral excursive (i.e., the patient&#39;s mandible shifted/rotated left and right while closed), hinging (i.e., the patient&#39;s mandible opening and closing without lateral movement), chewing (i.e., the patient&#39;s mandible chewing naturally to, for example, determine the most commonly used tooth contact points), and border movements (i.e., the patient&#39;s mandible is shifted in all directions while closed, for example, to determine the full range of motion) of the patient&#39;s jaw. This motion data  810  may be used to determine properties of the patient&#39;s temporomandibular joint (TMJ). For example, hinging motion of the motion data  810  may be used to determine the location of the hinge axis of the patient&#39;s TMJ. 
     The example dental lab  804  includes a 3D scanner  812 , a design system  816 , a rapid fabrication machine  819 , and an appliance fabrication station  822 . Although shown as a single dental lab in this figure, in some embodiments, the dental lab  804  comprises multiple dental labs. For example, in some embodiments, the 3D scanner  812  is in a different dental lab than one or more of the other components shown in the dental lab  804 . Further, in some embodiments, one or more of the components shown in the dental lab  804  are not in a dental lab. For example, in some embodiments, one or more of the 3D scanner  812 , dental splint design system  816 , rapid fabrication machine  819 , and appliance fabrication station  822  are in the dental office  802 . Additionally, some embodiments of the system  800  do not include all of the components shown in the dental lab  804 . 
     The example 3D scanner  812  is a device configured to create a three-dimensional digital representation of the dental impression  808 . In some embodiments, the 3D scanner  812  generates a point cloud, a polygonal mesh, a parametric model, or voxel data representing the dental impression  808 . In some embodiments, the 3D scanner  812  generates a digital dental model  814 . In some embodiments, the 3D scanner  812  comprises a laser scanner, a touch probe, or an industrial CT scanner. Yet other embodiments of the 3D scanner  812  are possible as well. Further, some embodiments of the system  800  do not include the 3D scanner  812 . For example, in some embodiments of the system  800  where the dental impression station  806  generates a digital dental impression, the 3D scanner  812  is not included. 
     The dental splint design system  816  is a system that is configured to generate the dental splint data  818 . In some embodiments, the dental splint data  818  is three-dimensional digital data that represents the dental splint component  820  and is in a format suitable for fabrication using the rapid fabrication machine  819 . 
     In some embodiments, the dental splint design system  816  comprises a computing device including user input devices. The design system  816  may include computer-aided-design (CAD) software that generates a graphical display of the dental splint data  818  and allows an operator to interact with and manipulate the dental splint data  818 . For example, the dental splint design system  816  may include digital tools that mimic the tools used by a laboratory technician to physically design a dental appliance. For example, some embodiments include a tool to move the patient&#39;s dentition according to the motion data  810 . Additionally, in some embodiments, the dental splint design system  816  includes a server that partially or fully automates the generation of designs of the dental splint data  818 , which may use the motion data  810 . 
     The dental splint design system  816  may be usable to design one or more dental appliance and/or dental treatment concurrently. The motion data  810  may be used to evaluate the interaction between the one or more dental appliance and/or dental treatment. This may be particularly beneficial in designing complex appliances and planning complex dental treatments such as implant supported denture systems. 
     In some embodiments, the rapid fabrication machine  819  comprises one or more three-dimensional printers, such as the ProJet line of printers from 3D Systems, Inc. of Rock Hill, S.C. Another example of the rapid fabrication machine  819  is stereolithography equipment. Yet another example of the rapid fabrication machine  819  is a milling device, such as a computer numerically controlled (CNC) milling device. In some embodiments, the rapid fabrication machine  819  is configured to receive files in the STL format. Other embodiments of the rapid fabrication machine  819  are possible as well. 
     Additionally, in some embodiments, the rapid fabrication machine  819  is configured to use the dental splint data  818  to fabricate the dental splint component  820 . In some embodiments, the dental splint component  820  is a physical component that is configured to be used as part or all of the motion-based dental splint  824 . For example, in some embodiments, the dental splint component is milled from a biocompatible plastic material or another material that is used directly as a dental splint. In other embodiments, the dental splint component  820  is a mold formed from wax or another material and is configured to be used indirectly (e.g., through a vacuum forming process) to fabricate the motion-based dental splint  824 . Further, in some embodiments, the dental splint component  820  is formed using laser sintering technology. 
     In some embodiments, the appliance fabrication station  822  fabricates a motion-based dental splint  824  for the patient. In some embodiments, the appliance fabrication station  822  uses the dental splint component  820  produced by the rapid fabrication machine  819 . In some embodiments, the motion-based dental splint  824  is a temporomandibular disorder (TMD) splint. Other embodiments of the motion-based dental splint  824  are possible as well. In some embodiments, the motion-based dental splint  824  is formed from an acrylic or plastic material. In some embodiments, the dental impression  808  is used in the fabrication of the motion-based dental splint  824 . In some embodiments, the dental impression  808  is used to form a plaster model of the dentition of the patient. Additionally, in some embodiments, a model of the dentition of the patient is generated by the rapid fabrication machine  819 . In some embodiments, the appliance fabrication station  822  includes equipment and processes to perform some or all of the techniques used in traditional dental laboratories to generate dental appliances. Other embodiments of the appliance fabrication station  822  are possible as well. 
     In some embodiments, the motion-based dental splint  824  is seated in the mouth of the patient in the dental therapy station  826  by a dentist. In some embodiments, the dentist confirms that the occlusal surface of the motion-based dental splint  824  is properly defined by instructing the patient to engage in various bites or perform various jaw motions. 
     Although many of the embodiments of the dental lab discussed herein receive motion data  810  from the motion capture system  100 , alternatives are possible. The motion data  810  may be received from any system that captures motion data of the patient or an existing record of the patient&#39;s motion. 
     Additionally, in some embodiments, the dental office  802  is connected to the dental lab  804  via a network. In some embodiments, the network is an electronic communication network that facilitates communication between the dental office  802  and the dental lab  804 . An electronic communication network is a set of computing devices and links between the computing devices. The computing devices in the network use the links to enable communication among the computing devices in the network. The network can include routers, switches, mobile access points, bridges, hubs, intrusion detection devices, storage devices, standalone server devices, blade server devices, sensors, desktop computers, firewall devices, laptop computers, handheld computers, mobile telephones, and other types of computing devices. 
     In various embodiments, the network includes various types of links. For example, the network can include one or both of wired and wireless links, including Bluetooth, ultra-wideband (UWB), 802.11, ZigBee, and other types of wireless links. Furthermore, in various embodiments, the network is implemented at various scales. For example, the network can be implemented as one or more local area networks (LANs), metropolitan area networks, subnets, wide area networks (such as the Internet), or can be implemented at another scale. 
       FIG.  16    is an example process  850  for designing a dental splint based on captured jaw motion. In some embodiments, the process  850  is performed by the system  800 . 
     At operation  852 , an impression of a patient&#39;s dentition is acquired. In some aspects, the impression is captured using a digital or physical impressioning technique. Alternatively, the impression is acquired from a storage location such as a database that stores dental impression data (e.g., from a previous patient visit). 
     At operation  854 , jaw motion data for the patient is captured. The motion data may for example be captured using the motion capture system  100  or another system for capturing patient motion. Some or all of the motion data may also be inferred based on an actual or inferred location of the patient&#39;s condyle with respect to the position of the patient&#39;s dentition in the impression received at operation  852 . Alternatively, the motion data is acquired from a storage location such as a database that stores dental motion data (e.g., from a previous patient visit). 
     At operation  856 , a thin-shell appliance is generated for the patient based on the impression. In some embodiments, the thin-shell appliance is formed for one arch of the patient&#39;s dentition (referred to herein as the splint arch). The thin-shell appliance may be generated by identifying a region of a surface of the splint arch, offsetting that region by a first amount to generate an inner surface of the thin-shell appliance, offsetting that region by a second amount to generate an outer surface of the thin-shell appliance, and joining the inner surface and the outer surface. For example, the region may be identified based on a desired tooth coverage for the thin-shell appliance, such as coverage of all of the teeth or coverage of just the anterior teeth. The region may further be identified to include the surfaces of the teeth starting from the gingival margin, the heights of contour, or a location in-between. The region may be identified automatically, based on user input, or any combination thereof. Offsetting the surface may include generating a copy of the surface of the identified region of the splint arch and moving each vertex of the copied surface out by a specified amount in a direction normal to the surface. The offsetting may also include various operations to ensure the surface remains manifold (i.e., does not intersect with itself) in regions where the surface normal direction changes rapidly. Non-uniform offsets may be applied in some implementations. 
     At operation  858 , a contact surface is generated based on the motion data. The contact surface may be a single continuous surface or multiple disjoint surfaces. In some implementations, the contact surface is generated based on moving the arch of the patient&#39;s dentition opposing the splint arch (referred to herein as the opposing arch) based on the motion data. The opposing arch may be moved relative to the splint arch. In some implementations, one or more contact regions are identified on the opposing arch. The contact regions may include, for example, regions of the opposing arch that should be in contact with the splint during a specific bite motion when the patient is wearing the splint. The contact regions may include portions of the occlusal surfaces (such as cusp tips or incisal edges) of the patient&#39;s teeth on the opposing arch. The contact regions may be identified automatically or based on user input. In some implementations, a user interface is provided to allow a dentist or other care provider to specify which teeth should be in contact. 
     In some implementations, vertices associated with contact regions may be identified. The contact surface may be generated based on a path swept by those vertices as the opposing arch is moved through a specific motion path relative to the splint arch. 
     In some implementations, the opposing arch is opened by a specified amount before moving through specific motion path to generate contact surface. For example, the opposing arch may be opened from a record closed bite (i.e., centric occlusion) position by performing a hinge motion to bring the opposing arch out of contact by the specified amount. In some implementations, the opposing arch may be initially positioned in a captured open bite (i.e., centric relation). 
     At operation  860 , the contact surface is joined with the thin-shell appliance. Various techniques may be used to join the contact surface to the thin-shell appliance. For example, the contact surface may be extended from a surface to a solid mesh (e.g., by joining the contact surface to a copy of the contact surface that is repositioned toward the gingival). The solid mesh may then be joined to the thin-shell appliance with a Boolean operation (e.g., a union). The contact surface may also be joined to the thin-shell appliance by deforming the outer surface of the thin-shell appliance to meet the contact surface. 
       FIG.  17    illustrates an example architecture of a computing device  950  that can be used to implement aspects of the present disclosure, including any of the plurality of computing devices described herein, such as a computing device of the motion determining device  106 , the design system  816 , or any other computing devices that may be utilized in the various possible embodiments. 
     The computing device illustrated in  FIG.  17    can be used to execute the operating system, application programs, and software modules described herein. 
     The computing device  950  includes, in some embodiments, at least one processing device  960 , such as a central processing unit (CPU). A variety of processing devices are available from a variety of manufacturers, for example, Intel or Advanced Micro Devices. In this example, the computing device  950  also includes a system memory  962 , and a system bus  964  that couples various system components including the system memory  962  to the processing device  960 . The system bus  964  is one of any number of types of bus structures including a memory bus, or memory controller; a peripheral bus; and a local bus using any of a variety of bus architectures. 
     Examples of computing devices suitable for the computing device  950  include a desktop computer, a laptop computer, a tablet computer, a mobile computing device (such as a smart phone, an iPod® or iPad® mobile digital device, or other mobile devices), or other devices configured to process digital instructions. 
     The system memory  962  includes read only memory  966  and random-access memory  968 . A basic input/output system  970  containing the basic routines that act to transfer information within computing device  950 , such as during start up, is typically stored in the read only memory  966 . 
     The computing device  950  also includes a secondary storage device  972  in some embodiments, such as a hard disk drive, for storing digital data. The secondary storage device  972  is connected to the system bus  964  by a secondary storage interface  974 . The secondary storage devices  972  and their associated computer readable media provide nonvolatile storage of computer readable instructions (including application programs and program modules), data structures, and other data for the computing device  950 . 
     Although the example environment described herein employs a hard disk drive as a secondary storage device, other types of computer readable storage media are used in other embodiments. Examples of these other types of computer readable storage media include magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, compact disc read only memories, digital versatile disk read only memories, random access memories, or read only memories. Some embodiments include non-transitory computer-readable media. Additionally, such computer readable storage media can include local storage or cloud-based storage. 
     A number of program modules can be stored in secondary storage device  972  or system memory  962 , including an operating system  976 , one or more application programs  978 , other program modules  980  (such as the software engines described herein), and program data  982 . The computing device  950  can utilize any suitable operating system, such as Microsoft Windows™, Google Chrome™ OS or Android, Apple OS, Unix, or Linux and variants and any other operating system suitable for a computing device. Other examples can include Microsoft, Google, or Apple operating systems, or any other suitable operating system used in tablet computing devices. 
     In some embodiments, a user provides inputs to the computing device  950  through one or more input devices  984 . Examples of input devices  984  include a keyboard  986 , mouse  988 , microphone  990 , and touch sensor  992  (such as a touchpad or touch sensitive display). Other embodiments include other input devices  984 . The input devices are often connected to the processing device  960  through an input/output interface  994  that is coupled to the system bus  964 . These input devices  984  can be connected by any number of input/output interfaces, such as a parallel port, serial port, game port, or a universal serial bus. Wireless communication between input devices and the interface  994  is possible as well, and includes infrared, BLUETOOTH® wireless technology, 802.11a/b/g/n, cellular, ultra-wideband (UWB), ZigBee, or other radio frequency communication systems in some possible embodiments. 
     In this example embodiment, a display device  996 , such as a monitor, liquid crystal display device, projector, or touch sensitive display device, is also connected to the system bus  964  via an interface, such as a video adapter  998 . In addition to the display device  996 , the computing device  950  can include various other peripheral devices (not shown), such as speakers or a printer. 
     When used in a local area networking environment or a wide area networking environment (such as the Internet), the computing device  950  is typically connected to the network through a network interface  1000 , such as an Ethernet interface or WiFi interface. Other possible embodiments use other communication devices. For example, some embodiments of the computing device  950  include a modem for communicating across the network. 
     The computing device  950  typically includes at least some form of computer readable media. Computer readable media includes any available media that can be accessed by the computing device  950 . By way of example, computer readable media include computer readable storage media and computer readable communication media. 
     Computer readable storage media includes volatile and nonvolatile, removable and non-removable media implemented in any device configured to store information such as computer readable instructions, data structures, program modules or other data. Computer readable storage media includes, but is not limited to, random access memory, read only memory, electrically erasable programmable read only memory, flash memory or other memory technology, compact disc read only memory, digital versatile disks or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and that can be accessed by the computing device  950 . 
     Computer readable communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” refers to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, computer readable communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared, and other wireless media. Combinations of any of the above are also included within the scope of computer readable media. 
     The computing device illustrated in  FIG.  17    is also an example of programmable electronics, which may include one or more such computing devices, and when multiple computing devices are included, such computing devices can be coupled together with a suitable data communication network so as to collectively perform the various functions, methods, or operations disclosed herein. 
     Some non-limiting examples are provided below: 
     Example 1: A dental appliance for a dental arch of a patient, the appliance comprising: an interior surface shaped to fit to contours of at least one tooth of the dental arch; and an exterior surface that includes at least one contact surface formed based on motion data. 
     Example 2: The dental appliance of example 1, wherein the exterior surface includes a contour-following surface that follows the contours of at least one tooth of the dental arch. 
     Example 3: The dental appliance of example 2, wherein the contour-following surface is an offset surface of the interior surface. 
     Example 4: The dental appliance of any one of examples 1-3, wherein the contact surface is disposed in an anterior region of the dental arch. 
     Example 5: The dental appliance of example 4, wherein the contact surface extends from cuspid to cuspid. 
     Example 6: The dental appliance of any one of examples 2-5, wherein the contour-following surface is disposed in at least one posterior region of the dental arch. 
     Example 7: The dental appliance of any one of examples 1-6, wherein the contact surface has a concave shape in a cross-arch dimension. 
     Example 8: The dental appliance of any one of examples 1-7, wherein the contact surface has shape that corresponds to a shape formed by sweeping a point from an opposing dental arch through a motion path relative to the dental arch, the motion path being based on the motion data. 
     Example 9: The dental appliance of example 8, wherein the contact surface has shape that corresponds to a shape formed by sweeping a point from the opposing dental arch through a protrusive motion path relative to the dental arch. 
     Example 10: The dental appliance of any of examples 8 or 9, wherein the contact surface has shape that corresponds to a shape formed by hinging the opposing arch open by a specific amount and sweeping a point from the opposing dental arch through a motion path relative to the dental arch. 
     Example 11: The dental appliance of any one of examples 1-10, wherein the contact surface is offset in an occlusal direction by a predetermined amount. 
     Example 12: The dental appliance of example 11, wherein the predetermined amount is based on a centric relation bite of the patient. 
     Example 13: The dental appliance of any one of examples 1-12, wherein the contact surface is raised occlusally in an anterior region and slopes away toward a posterior region. 
     Example 14: The dental appliance of any one of examples 1-13, wherein the contact surface is shaped so that when the dental appliance is worn by the patient, some or all of the opposing dental arch remains in contact with the contact surface throughout a motion path from the motion data. 
     Example 15: The dental appliance of example 14, wherein the contact surface is shaped so that when the dental appliance is worn by the patient, at least one cuspid of an opposing dental arch of the patient remains in contact with the contact surface throughout a protrusive motion path from the motion data. 
     Example 16: The dental appliance of example 14, wherein the contact surface is shaped so that when the dental appliance is worn by the patient, at least one anterior tooth of an opposing dental arch of the patient remains in contact with the contact surface throughout an excursive motion path from the motion data. 
     Example 17: The dental appliance of example 16, wherein the at least one anterior tooth includes an incisor. 
     Example 18: The dental appliance of any one of examples 1-17, wherein the contact surface is shaped so that when the dental appliance is worn by the patient, contact force is balanced approximately evenly across all opposing teeth that are in contact. 
     Example 19: The dental appliance of any one of examples 1-18, wherein the contact surface includes at least one contact ridge. 
     Example 20: The dental appliance of example 19, wherein the at least one contact ridge includes a raised ridge on the contact surface. 
     Example 21: The dental appliance of example 20, wherein the at least one contact ridge includes a cuspid contact ridge that is positioned based on a contact region of a cuspid of an opposing dental arch of the patient. 
     Example 22: The dental appliance of example 21, wherein the cuspid contact ridge has a shape that corresponds to a shape formed by sweeping the contact region through a protrusive motion path relative to the dental arch. 
     Example 23: The dental appliance of any one of examples 21 or 22, wherein the at least one contact ridge includes an incisor contact ridge that is positioned based on a contact region of an incisor of an opposing dental arch of the patient. 
     Example 24: The dental appliance of example 23, wherein the incisor contact ridge has a shape that corresponds to a shape formed by sweeping the contact region through an excursive motion path relative to the dental arch. 
     Example 25: The dental appliance of any one of examples 23 or 24, wherein the incisor contact ridge includes an extreme lateral region. 
     Example 26: The dental appliance of example 25, wherein the extreme lateral region has a shape that corresponds to a shape formed by sweeping the contact region from a standard bite to a cross-bite. 
     Example 27: The dental appliance of any one of examples 1-26, wherein the motion data includes relative motion data on movement of the dental arch relative to an opposing dental arch of the patient. 
     Example 28: The dental appliance of example 27, wherein the dental arch is a lower arch and the opposing dental arch is an upper arch. 
     Example 29: The dental appliance of any one of examples 1-28, wherein the appliance is usable for treatment of temporomandibular joint disorders. 
     Example 30: A method comprising: acquiring an impression of a patient&#39;s dentition; acquiring motion data for the patient; generating a thin-shell appliance for the patient based on the impression; generating a contact surface based on the motion data; and joining the contact surface with the thin-shell appliance. 
     Example 31: The method of example 30, wherein the acquiring an impression includes capturing three-dimensional scan data with an intraoral scanner. 
     Example 32: The method of any one of examples 30 or 31, wherein the acquiring motion data for the patient includes capturing motion data with a motion capture system. 
     Example 33: The method of example 32, wherein the capturing motion data with a motion capture system includes: coupling a first clutch to a first dental arch of a patient&#39;s dentition; coupling a second clutch to a second dental arch of a patient&#39;s dentition; capturing motion data using a first position indicator system of the first clutch; capturing motion data using a second position indicator system of the second clutch; and determining motion of the first dental arch relative to the second dental arch based on the captured motion data from the first position indicator and the second position indicator. 
     Example 34: The method of any one of examples 31-33, wherein the acquiring motion data for the patient includes acquiring excursive motion data. 
     Example 35: The method of any one of examples 31-34, wherein the acquiring motion data for the patient includes acquiring protrusive motion data. 
     Example 36: The method of any one of examples 31-35, wherein the acquiring motion data for the patient includes acquiring extreme lateral motion data. 
     Example 37: The method of any one of examples 31-36, wherein the generating a thin-shell appliance for the patient based on the impression includes: identifying a portion of a surface of a dental arch in the impression; generating an interior offset surface based on offsetting three-dimensional data representing the identified portion by a first offset amount; generating an exterior offset surface; and joining the interior offset surface to the exterior offset surface. 
     Example 38: The method of example 37, wherein the generating an exterior offset surface includes generating the exterior offset surface based on offsetting three-dimensional data representing a dental arch from the impression by a second amount. 
     Example 39: The method of example 37, wherein the generating an exterior offset surface includes generating the exterior offset surface based on offsetting the interior offset surface by a second amount. 
     Example 40: The method of any one of examples 37-39, wherein the joining the interior offset surface to the exterior offset surface includes: generating an edge surface connecting the interior offset surface to the exterior offset surface. 
     Example 41: The method of any one of examples 37-40, wherein the identifying the portion of the surface of the dental arch in the impression includes: identifying heights of contour of the dental arch; and extending the portion beyond the heights of contour. 
     Example 42: The method of any one of examples 30-41, wherein the generating a contact surface based on the motion data includes: generating a contact surface disposed in an anterior region of a dental arch. 
     Example 43: The method of any one of examples 30-42, wherein the generating a contact surface based on the motion data includes generating a contact surface that has a concave shape in a cross-arch dimension. 
     Example 44: The method of example 43, wherein the generating a contact surface that has a concave shape in the cross-arch dimension includes sweeping a point from an opposing dental arch through a motion path relative to the dental arch, the motion path being based on the motion data. 
     Example 45: The method of example 44, wherein the sweeping a point from an opposing dental arch through a motion path includes sweeping the point from an opposing dental arch through a protrusive motion path relative to the dental arch. 
     Example 46: The method of any one of examples 44 or 45, wherein the generating a contact surface that has a concave shape in the cross-arch dimension includes: moving the opposing dental arch through a hinge motion path in the motion data to position the opposing dental arch in an open position; and sweeping a point of the opposing dental arch in the open position arch through a motion path relative to the dental arch. 
     Example 47: The method of any one of examples 46, wherein the moving the opposing dental arch through a hinge motion path in the motion data to open the bite by an amount based on a centric relation bite of the patient. 
     Example 48: The method of any one of examples 43-45, wherein the generating a contact surface that has a concave shape in the cross-arch dimension includes: positioning the opposing dental arch in a centric relation bite position based on the motion data; and sweeping a point of the opposing dental arch in the centric relation bite position arch through a motion path relative to the dental arch. 
     Example 49: The method of any one of examples 30-48, wherein the contact surface is raised occlusally in an anterior region and slopes away posteriorly. 
     Example 50: The method of any one of examples 30-49, wherein the contact surface is shaped so that when the thin-shell appliance is worn by the patient, at least a portion of the opposing dental arch remains in contact with the contact surface throughout a motion path from the motion data. 
     Example 51: The method of example 50, wherein the contact surface is shaped so that when the thin-shell appliance is worn by the patient, at least one cuspid of the opposing dental arch remains in contact with the contact surface throughout a protrusive motion path from the motion data. 
     Example 52: The method of example 50, wherein the contact surface is shaped so that when the thin-shell appliance is worn by the patient, at least one incisor of the opposing dental arch remains in contact with the contact surface throughout an excursive motion path from the motion data. 
     Example 53: The method of example 50, wherein the contact surface is shaped so that when the thin-shell appliance is worn by the patient, contact force is balanced approximately evenly across a plurality of teeth of the opposing dental arch. 
     Example 54: The method of any one of examples 30-53, wherein the generating a contact surface based on the motion data includes generating at least one contact ridge based on the motion data. 
     Example 55: The method of example 54, wherein the generating at least one contact ridge based on the motion data includes: identifying a contact region of an opposing dental arch; and sweeping the contact region through a motion path relative to the dental arch. 
     Example 56: The method of example 55, wherein the generating at least one contact ridge based on the motion data further includes deforming a mesh based on the sweeping the contact region. 
     Example 57: The method of example 55, wherein the generating at least one contact ridge based on the motion data further includes generating a mesh based on the sweeping the contact region; and joining the generated mesh with the contact surface. 
     Example 58: The method of any one of examples 55-57, wherein: the identifying a contact region of the opposing dental arch includes identifying a contact region on a cuspid of the opposing dental arch; and the sweeping the contact region through the motion path relative to the dental arch includes sweeping the contact region through a protrusive motion path relative to the dental arch. 
     Example 59: The method of any one of examples 55-58, wherein: the identifying a contact region of the opposing dental arch includes identifying a contact region on an incisor of the opposing dental arch; and the sweeping the contact region through the motion path relative to the dental arch includes sweeping the contact region through an excursive motion path relative to the dental arch. 
     Example 60: The method of example 59, wherein the generating at least one contact ridge based on the motion data further includes sweeping the contact region through an extreme lateral motion path that corresponds to the opposing dental arch moving form an open bite to a cross bite relative to the dental arch. 
     Example 61: The method of any one of examples 30-60, wherein the joining the contact surface with the thin-shell appliance includes: generating a solid mesh from the contact surface; and joining the solid mesh to the thin-shell appliance using a Boolean operation. 
     Example 62: The method of any one of examples 30-60, wherein the joining the contact surface with the thin-shell appliance includes deforming an exterior surface of the thin-shell appliance based on the contact surface. 
     Example 63: The method of any one of examples 30-62, further comprising: fabricating a physical appliance from the thin-shell appliance using a rapid fabrication machine. 
     Example 64: The method of example 63, further comprising providing the physical appliance to the patient for treatment of temporomandibular joint disorder. 
     Example 65: A non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, cause a computing system to perform the method of any of examples 30-63. 
     Example 66: A computing device comprising: at least one processor; and memory storing instructions that, when executed by the at least one processor, cause the computing device to perform the method of any of examples 30-63. 
     Example 67: A system comprising: an intraoral scanner for acquiring an impression of a patient&#39;s dentition; a motion capture system for acquiring motion data for the patient; and the computing device of example 66. 
     Example 68: The system of example 67, further comprising a rapid fabrication machine for fabricating a physical appliance. 
     Example 69: A dental splint comprising a thin-shell aligner and a contact surface. The contact surface may be formed based on motion data. In some implementations, the motion data includes relative motion data on movement of a patient&#39;s upper dentition with respect to the patient&#39;s lower dentition. The contact surface may include one or more ridges corresponding to the positions of a contact region on the opposing dentition as a jaw movement is performed. In some examples, the dental splint is used for treatment of temporomandibular joint disorder. 
     Example 70: A method comprising: acquiring an impression of a patient&#39;s dentition; acquiring jaw motion data for the patient; generating a thin-shell appliance for the patient based on the impression; generating a contact surface based on the motion data; and joining the contact surface with the thin-shell appliance.