[0001] This application is being filed on 9 December 2016, as a PCT

International patent application, and claims priority to U.S. Provisional Patent Application No. 62/266,549, filed December 11, 2015, U.S. Provisional Patent Application No. 62/328,837, filed April 28, 2016, and U.S. Provisional Patent Application No. 62/359,291, filed July 7, 2016, the disclosures of which are hereby incorporated by reference in their entirety. BACKGROUND

[0002] Understanding and recording an accurate static relationship between teeth in a patient's upper jaw and lower jaw is an important first step in the art and science of designing dental restorations and other planning dental or surgical interventions that affect dental/skeletal function and aesthetics of the facial musculature system.

[0003] 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 best 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.

[0004] 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, occlusal splints, orthodontic retainers, and orthodontic aligners. A dental restoration 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'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's dentition.

[0005] 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.

SUMMARY

[0006] In general terms, this disclosure is directed to a system for measuring jaw movement. In one possible configuration and by non-limiting example, a patient assembly is coupled to a patient's dentition and imaging system captures images of the patient assembly as the patient's dentition moves.

[0007] One aspect is a patient assembly for capturing motion data of a patient comprising: a clutch configured to be worn by the patient on a dentition of the patient, the clutch comprising: a dentition coupling device configured to couple to the dentition of the patient, the dentition coupling device including an extension member configured to protrude through the patient's mouth; and a position indicating system rigidly connected to the dentition coupling device.

[0008] Another aspect is A patient assembly for capturing motion data of a patient comprising: a clutch configured to be worn by the patient on a dentition of the patient, the clutch comprising: a dentition coupling device configured to couple to the dentition of the patient, the dentition coupling device including an extension member configured to protrude through the patient's mouth; a housing configured to rigidly connect to the extension member of the dentition coupling device; at first light emitter disposed within the housing and oriented to emit light in a first direction; a second light emitter disposed within the housing and oriented to emit light in a second direction, the second direction being perpendicular to the first direction; and a third light emitter disposed within the housing and oriented to emit light in a third direction, the third direction being opposite of the first direction.

[0009] Yet another aspect is a motion capture system for capturing jaw movement of a patient, the system comprising: a patient assembly configured to be worn by the patient, the patient assembly comprising a clutch configured to be worn on an arch of the patient's dentition and a reference structure configured to be worn on the opposite arch, the clutch being configured to emit a plurality of light beams; an imaging system configured to capture a plurality of image sets, wherein each image set comprises a plurality of images and each image of the plurality of images includes at least one of a plurality of screens; and a motion determining device configured to process image sets captured by the imaging system to determine the motion of the patient's dentition.

[0010] 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.

[0011] 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

[0012] FIG. 1 is a schematic block diagram illustrating an example motion capture system for capturing jaw and facial movement.

[0013] FIG. 2 illustrates a block diagram of an example patient assembly of FIG. 1.

[0014] FIG. 3 illustrates an example embodiment of the clutch of FIG. 2.

[0015] FIG. 4 illustrates an example impression device that is configured to mate with the dentition coupling framework of FIG. 3.

[0016] FIG. 5 illustrates an example embodiment of a dentition coupling framework of the clutch or reference structure of FIG. 3. [0017] FIG. 6 illustrates an embodiment of the patient assembly of FIG. 1.

[0018] FIG. 7 illustrates another embodiment of the patient assembly of FIG. 1.

[0019] FIG. 8 illustrates another embodiment of the patient assembly of FIG. 1.

[0020] FIG. 9 illustrates another embodiment of the patient assembly of FIG. 1.

[0021] FIG. 10 illustrates another embodiment of the patient assembly of FIG. 1.

[0022] FIG. 11 illustrates an embodiment of the patient assembly of FIG. 1 that includes a position indicating fiducial marker.

[0023] FIG. 12 illustrates an example embodiment of a position-indicating fiducial marker.

[0024] FIG. 13 illustrates an example embodiment of the clutch of FIG. 2.

[0025] FIG. 14 illustrates a top view of an embodiment of the reference structure of FIG. 2 and an embodiment of the imaging system of FIG. 1.

[0026] FIG. 15 illustrates another embodiment of the patient assembly of FIG. 1.

[0027] FIG. 16 illustrates an example of a light source assembly and an embodiment of the clutch position indicator of FIG. 2.

[0028] FIG. 17 illustrates an example of an imaging system of FIG. 1.

[0029] FIG. 18 illustrates a perspective view of part of the embodiment of the reference structure of FIG. 20 and an embodiment of the clutch of FIG. 2.

[0030] FIG. 19 illustrates a perspective view of part of the embodiment of the reference structure of FIG. 20.

[0031] FIG. 20 illustrates a top view of an embodiment of the reference structure of FIG. 2 and an embodiment of the imaging system of FIG. 1.

[0032] FIG. 21 illustrates a perspective view of part of the embodiment of the reference structure of FIG. 20 and of the imaging system of FIG. 19.

[0033] FIG. 22 illustrates an embodiment of a head-mounted patient assembly and imaging system.

[0034] FIG. 23 illustrates another embodiment of a head-mounted patient assembly and imaging system.

[0035] FIG. 24 includes a detailed illustration of a joint of the head-mounted patient assembly and imaging system of FIG. 23.

[0036] FIG. 25 is a top-view of an embodiment of the head-mounted patient assembly and imaging system of FIG. 23. [0037] FIG. 26 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 dental appliance or provide dental therapy.

[0038] FIG. 27 is an example process for designing a dental appliance or treatment based on captured jaw motion performed by embodiments of the system of FIG. 1.

[0039] FIG. 28 is an example process for determining relative motion of the patient's upper and lower dentition based on images captured by the imaging system of FIG. 1 that is performed by embodiments of the motion determining device of FIG. 1.

[0040] FIG. 29 illustrates an example transfer assembly usable with

embodiments of a clutch of the patient assembly of FIG. 1.

[0041] FIG. 30 illustrates an example architecture of a computing device, which can be used to implement aspects according to the present disclosure.

DETAILED DESCRIPTION

[0042] 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.

[0043] The present disclosure relates to a jaw and facial movement measurement system. For example, the system may record the motion of a patient's mandible relative to the patient's maxilla. In some embodiments, the system operates to infer 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.

[0044] In embodiments, the recorded motion is applied to a three-dimensional digital model of at least a portion of the patient's dentition. This motion can then be used while designing dental appliances or planning various dental therapies for the patient. In this manner, the appliances and therapies can be designed based on analysis of a range of actual motion for the patient. This may be especially beneficial when designing complex restorations such as bridges, implants, or implant- supported prosthesis for the treatment of edentulous or partially edentulous dentitions as well as in providing dental therapies such as oral-maxillofacial reconstructive surgery.

[0045] FIG. 1 is a schematic block diagram illustrating an example motion capture system 100 for capturing jaw and facial movement. 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.

[0046] In some embodiments, the imaging system 102 is an optical sensing device that captures a plurality of images of the patient assembly 104 as the patient's jaw moves. For example, the imaging system 102 may comprise one or more cameras such as video cameras. As another example, the imaging system 102 may capture 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 (e.g., the patient assembly may emit lights and some embodiments capture images of surfaces upon which those lights are projected).

[0047] In some embodiments, multiple cameras of the imaging system 102 capture images of the patient assembly 104 from different positions. Based on these images, the three-dimensional location of various portions of the patient assembly 104 may be determined, for example, using computer stereo vision.

[0048] Additionally, in some embodiments, the imaging system 102 includes a projector such as a light projector or laser projector that operates to project a pattern on the patient assembly 104 (and in some embodiments the patient). For example, the projector may be offset relative to the camera or cameras so that the images captured by the camera include distortions of the projected pattern caused by one or both of the patient assembly 104 and the surface geometry of the patient's face. Based on these distortions, the three dimensional structure of portions of the patient assembly 104 or patient's face can be approximated. Various embodiments project various patterns such as one or more stripes or fringe patterns (i.e., sinusoidally changing intensity values).

[0049] 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. Alternatively or additionally, a frame rate (e.g., 10 frames/second, 24 frames/second, 60 frames/second) is 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, or of settings used when capturing the image.

[0050] 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. In some embodiments, at least some portions of the patient assembly may limit the motion of the patient when secured thereto.

[0051] In some embodiments, the patient assembly 104 includes aspects that are configured to be imaged using the imaging system 102 and that can be used to determine the position of the patient assembly 104. The patient assembly 104 may include one or more fiducial markers. Alternatively or additionally, the patient assembly 104 may include light emitters that emit a pattern of light that projects on one or more surfaces, which can be imaged to determine the position of the patient assembly 104.

[0052] In some embodiments, the patient assembly comprises 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.

[0053] 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 comprises 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's jaw is in different positions. Based on the determined three-dimensional coordinates of the patient assembly, some embodiments determine the relative positions and movements of the patient'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's mandible (including the lower dentition) about the temporomandibular j oint. [0054] Some embodiments of the motion determining device 106 also determine velocity and/or acceleration of the patient's dentition based on, for example, timestamps or other indicators of relative time associated with the images. The velocity and/or acceleration can be further analyzed to identify portions of the dentition's movement in which the movement is not smooth (e.g., changes in velocity or direction that exceed a predetermined threshold or expected value). These perturbations can be flagged visually or otherwise (e.g., highlighted during animations/simulations, etc.). The velocity information can, for example, be used to identify perturbations in the joint or the way portions of the patient's dentition fit together, which may be caused by tears in the meniscus of the joint that cause the joint to lock briefly. An ideal joint will move smoothly and will have a uniform or smooth velocity through the range of motion. When these perturbations are identified they can be used to guide crown or restoration design thus reducing the likelihood of failure or a restoration or other therapeutic intervention.

[0055] Examples of the motion determining device 106 and operations it performs are illustrated and described throughout, including in FIGS. 27-28.

[0056] FIG. 2 illustrates a block diagram of an example patient assembly 104. In this example, the patient assembly comprises a clutch 120 and a reference structure 122.

[0057] The clutch 120 is a device that is configured to couple to a patient'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, a framework 126, 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's mandible. In other embodiments, the clutch 120 may be configured to couple to the patient's upper dentition so as to move with the patient's maxilla.

[0058] The dentition coupling device 124 is configured to removably couple to the patient's dentition. In some embodiments, the dentition coupling device 124 rigidly couples to the patient's dentition such that while coupled, the movement of the dentition coupling device 124 relative to the patient's dentition is minimized. Various embodiments include various coupling mechanisms.

[0059] For example, some embodiments couple to the patient's dentition using brackets that are adhered to the patient's teeth with a dental or orthodontic adhesive. As another example, some embodiments couple to the patient'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's dentition, the impression tray is filled with impression material and then placed over the patient's dentition. As the impression material hardens, the dentition coupling device 124 couples to the patient's dentition.

[0060] 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'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, South Carolina. 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's dentition.

[0061] Embodiments of the dentition coupling device 124 may be operable to couple to the patient'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's dentition. For example, the temporary anchorage devices may screw into the patient's bone tissue to secure the dentition coupling device 124. An example of a dentition coupling device that is secured using a temporary anchorage device is illustrated and described with respect to at least FIG. 5.

[0062] In some embodiments, the dentition coupling device 144 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 140 and the patient's dentition. For example, the dentition coupling device 144 may include three fiducial markers disposed evenly along its surface. The location of these fiducial markers can then be determined relative to the patient'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.

[0063] The framework 126 is a rigid structure that extends away from the dentition coupling device 124 and connects the dentition coupling device 124 to the position indicator system 128. In some embodiments, the framework 126 is configured to extend out of the patient's mouth when the dentition coupling device 124 is coupled to the patient's dentition.

[0064] In some embodiments, the framework 126 includes one or more arms that extend away from the patient's mouth and are configured to dispose the position indicator system 128 in a location that can be used to determine the orientation of the framework 126 (and consequently the dentition coupling device 124 and the patient's dentition to which the dentition coupling device 124 is coupled). In some embodiments, the framework 126 is formed from a rigid or semi-rigid material, such as plastic, metal, ceramic, or a composite material.

[0065] In some embodiments the framework 126 and the dentition coupling device 124 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). Alternatively, the framework 126 includes a coupling structure configured to removably couple to the dentition coupling device 124. In this manner, the dentition coupling device 124 can be a disposable component that may be custom fabricated for each patient, while the framework 126 may be reused with multiple dentition coupling devices. In some embodiments, the framework 126 includes a connector that is configured to mate with a connector on the dentition coupling device 124. Additionally or alternatively, the framework 126 may couple to the dentition coupling device 124 with a magnetic clasp.

[0066] 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. [0067] In other embodiments, the position indicator system 128 includes a single fiducial marker that includes surface markings that can be analyzed to determine the orientation of the fiducial marker. For example, the fiducial marker may be a sphere that has a non-uniform pattern across its surface. Based on the portion of the pattern that is visible in an image, the orientation of the fiducial marker relative to the imaging system 102 can be determined.

[0068] Alternatively, the position indicator system 128 comprises 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 130 so that as the dentition coupling device 130 moves with the patient's dentition, the beams of light move. The position of the dentition coupling device 130 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 with respect to at least FIGS. 13-21.

[0069] 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's lower dentition, the reference structure 122 is configured to mount elsewhere on the patient's head so that the motion of the clutch 120 (and the patient's mandible) can be measured relative to the rest of the patient'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'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). Alternatively, the reference structure 122 may be configured to be worn elsewhere on the patient's face or head.

[0070] 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., 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, a framework 132 that may be similar to the framework 126, and a position indicator system 134 that may be similar to the position indicator system 128. [0071] FIG. 3 illustrates an example embodiment of a clutch 160. The clutch 160 is an example of the clutch 120. In this example, the clutch 160 includes a dentition coupling framework 170, a framework 172, and fiducial markers 174a, 174b, 174c, 174d, 174e, and 174f (referred to collectively as fiducial markers 174). In this example, the clutch 160 also includes an impression device 200 that is not shown in FIG. 3, but is illustrated and described with respect to at least FIG. 4. The dentition coupling framework 170 when combined with the impression device 200 is an example of the dentition coupling device 124, the framework 172 is an example of the framework 126, and the fiducial markers 174 together are an example of the position indicator system 128.

[0072] The dentition coupling framework 170 includes a dentition facing surface 176, a contact surface 178, and an extension member 182. The dentition facing surface 176 is configured to align with the patient's dentition and face towards the occlusal surface of the patient's dentition. In this example, the dentition facing surface 176 is configured to hold an impression tray, which may be secured to the dentition coupling framework 170 using one or more fastening devices such as screws. In this example, the dentition facing surface 176 includes holes 180 that are configured for use with fastening devices to couple to an impression tray. In other embodiments, the dentition coupling framework 170 is configured to couple directly to the patient's dentition or is configured to attach to another type of coupling device such as a mold shaped to fit the patient's dentition.

[0073] The contact surface 178 is configured to contact the patient's opposing dentition or a structure coupled to the patient's opposing dentition such as the reference structure 122. In the example shown, the contact surface 178 includes three regions that have generally flat surfaces for contact. The holes 180 are recessed between these regions of the contact surface 178. In some embodiments, the regions of the contact surface 178 are generally parallel with the dentition facing surface. However, the surfaces typically face opposite directions. In some embodiments, the contact surface 178 is separated from the dentition facing surface 176 by a distance D. This distance D essentially corresponds to the height of the dentition coupling device in the occlusal dimension. In some embodiments, the distance D is selected so as to permit the top of a fastening device (e.g., screw heads or knobs) to extend up from the holes 180 without extending to the contact surface 178. Beneficially, such an arrangement prevents the fastening device from making contact with the patient's opposing dentition or the reference structure 122.

[0074] Additionally, in some embodiments, the distance D is selected to create a desired occlusal separation between the patient's lower dentition and upper dentition. In some embodiments, the distance D is equal to half of the desired occlusal separation so that the patient can wear a reference structure 122 that also has a similar height and in combination with the clutch 160 causes the patent's lower dentition and upper dentition to be separated by a desired amount. In some embodiments, the desired amount of occlusal separation is configurable based on the patient's dental anatomy.

[0075] The extension member 182 extends from the dentition coupling framework 170 and is configured to extend out of the patient's mouth when the dentition coupling framework 170 is worn on the patient's dentition. In some embodiments, the extension member 182 is configured so as to be permanently attached to the framework 172 such as by being formed integrally or joined via welding or a permanent adhesive. In other embodiments, the extension member 182 is configured to removably attach to the framework 172. For example, as shown in FIG. 3, the extension member 182 includes a hole 184, which is configured to receive a fastening device (e.g., a screw) to fasten the extension member 182 to the framework 172. In some embodiments, one or both of the extension member 182 and the framework 172 includes alignment structures such as protrusions, ridges, or notches that are configured to cause the extension member 182 and the framework 172 to join together in a uniform and repeatable manner. Additionally or

alternatively, some embodiments use magnets to couple the extension member 182 and the framework 172.

[0076] In the embodiment shown, the framework 172 includes a central member 186 and arms 188a, 188b, 188c, and 188d (collectively referred to as arms 188). The central member 186 is configured to extend out laterally (i.e., towards the sides of the patient's face) from the extension member 182. In various embodiments, the central member 186 has various lengths. Because the central member 186 is rigidly coupled to the dentition coupling device, the position and orientation of the dentition coupling device can be determined from the position and orientation of the central member 186. In some embodiments, the length of the central member 186 is greater that the width of the dentition coupling framework 170 so as to magnify changes in orientation of the dentition coupling framework 170. Beneficially, this magnification may permit more accurate determination of the orientation of the dentition coupling framework 170 than would otherwise be possible with a particular imaging system. In various embodiments, one or more of the fiducial markers 174 are coupled directly to the central member 186.

[0077] Additionally or alternatively, one or more of the fiducial markers 174 are coupled to the arms 188. The arms are rigid bodies that are rigidly coupled to the central member 186. The arms 188 are configured to dispose the fiducial markers 174 so that the position and orientation of the central member 186 can be determined from the locations of the fiducial markers 174. In various embodiments, the arms 188 have various lengths. Much like the size of the central member operates to magnify changes in orientation of the dentition coupling device, the length of the arms 188 operate to magnify changes in the orientation of the central member 186. For example, a small rotation about the long axis of the central member (e.g., the axis running between the fiducial marker 174b and the fiducial marker 174f) would cause a larger movement in the position of the fiducial marker 174d due to the length of the arm 188c.

[0078] Various embodiments of the clutch 160 include various numbers of the arms 188 and various numbers of the fiducial markers 174 arranged in various configurations. In some embodiments, the clutch 160 includes three fiducial markers 174 that are arranged in a non-collinear fashion (i.e., the three fiducial markers 174 do not lie along a straight line). In these embodiments, when the three-dimensional positions of the three fiducial markers 174 are determined using the imaging system, the position and orientation of the clutch 160 can be determined. For example, the positions of the three fiducial markers 174 can be used to define a plane having a fixed and known relationship to the position and orientation of the clutch 160.

Additionally, in some embodiments, the direction of a vector formed between two of the fiducial markers is used further determine the orientation of the clutch 160. For example, by determining the vector running from the fiducial marker 174f to the fiducial marker 174e, the direction corresponding to the bottom of the clutch 160 can be determined.

[0079] Additionally, some embodiments include more than three fiducial markers 174. For example, in FIG. 3, the clutch 160 includes six of the fiducial markers 174. As shown in FIG. 3, the fiducial markers 174b and 174f are coupled directly to the central member 186 but disposed on opposite ends of the central member 186. The fiducial markers 174a and 174c are disposed on the arms 188a and 188b, respectively. The arms 188a and 188b are disposed at a right angle from one another extending out from the central member 186. The fiducial markers 174d and 174e are disposed on the arms 188c and 188d, respectively. The arms 188c and 188d are disposed at a right angle from one another extending out from the central member 186.

[0080] In embodiments that include more than three of the fiducial markers 174, it may be possible to determine the position and orientation of the clutch when some of the fiducial markers 174 are occluded. Additionally, in some embodiments, an error checking routine may be used to evaluate whether the positions of the fiducial markers 174 have been correctly determined. For example, when the position and orientation of the clutch 160 calculated using the positions of the fiducial markers 174a, 174b, and 174c matches the position and orientation of the clutch 160 calculated using the positions of the fiducial markers 174d, 174e, and 174f, it may be determined that the positions of the fiducial markers 174 have been determined correctly. In some embodiments, a match is determined when the two calculated positions and the two calculated orientations are within predetermined error thresholds of one another. In some embodiments, if it is determined that either the position or orientation do not match, the data may be excluded from use.

[0081] Alternatively, the positions and orientations may be compared to a position and orientation determined from one or more different sets of three of the markers (e.g., 174a, 174b, and 174f; 174d, 174f, and 174b; 174e, 174c, and 174a; etc.). By calculating the positions and orientations, using multiple sets of three fiducial markers, it can be determined if the position of one of the fiducial markers is likely to have been miscalculated (e.g., the positions and orientations calculated using each of the sets of three of the fiducial markers 174 match except for the sets that include a particular one of the fiducial markers 174). The fiducial marker that is identified as being miscalculated may then be excluded from the calculations.

[0082] FIG. 4 illustrates an example impression device 200 that is configured to mate with the dentition coupling framework 170 to form an embodiment of the dentition coupling device 124. The illustration in FIG. 4 shows the part of the impression device 200 that would face the patient's dentition oriented toward the top. Thus, the illustration in FIG. 4 shows the impression device 200 rotated 180 degrees from how it would be oriented when mated with the dentition coupling framework 170 of FIG. 3.

[0083] In this example, the impression device 200 includes an inner surface 202 that forms a trough 204 that roughly approximates the shape of the dental arch. In some embodiments, the cross-sections of the inner surface 202 (i.e., that are made perpendicular to the dental arch) are also arch shaped. The trough 204 is configured to hold a securing material such as impression material or an adhesive material that operates to secure the impression device to the dentition of the patient. Additionally, in some embodiments, the impression device 200 also includes one or more internal fiducial markers 206, a mating surface 208, and one or more fastening structures 210.

[0084] The internal fiducial markers 206 may be similar to the fiducial markers 174. However, in at least some embodiments, the internal fiducial markers 206 are smaller than the fiducial markers 174 so as to fit in the patient's mouth more comfortably. Additionally, in some embodiments, the internal fiducial markers 206 may be removable, so that the internal fiducial markers 206 can be removed when the impression device 200 is placed in a patient's mouth. The internal fiducial markers 206 are configured so that when imaged (e.g., by the imaging system 102), the position of the internal fiducial markers 206 can be determined. Various embodiments include various numbers of internal fiducial markers.

[0085] In some embodiments, the internal fiducial markers 206 are imaged when the impression device 200 is coupled to the dentition coupling framework 170 and the framework 172 to determine or confirm the relationship between the position of the impression device 200 and the fiducial markers 174 that are attached to the framework 172. However, in some embodiments, the relationship between the position of the impression device 200 and the fiducial markers 174 is determined based on a known fixed relationship between the devices and thus it is not necessary to capture images containing both the internal fiducial markers 206 and the fiducial markers 174.

[0086] In some embodiments, the internal fiducial markers 206 are imaged with an impression taken using the impression device 200 (e.g., hardened impression material in the trough 204) to determine a relationship between the position of the patient's dentition and the impression device 200 (and therefore the rest of the clutch [0087] The mating surface 208 is configured to fit against the dentition facing surface 176 when the impression device 200 is coupled to the dentition coupling framework 170. Additionally, the fastening structures 210 are configured to align with the holes 180 of the dentition coupling framework 170 and operate to join the impression device 200 to the dentition coupling framework 170. In some embodiments, the fastening structures 210 are knobs that fit through the holes 180 and may contain a hole for a screw or another fastener. Alternatively, the knobs and holes may be oblong shaped so that when mated the knobs can be twisted to secure the impression device 200 to the dentition coupling framework 170. Other embodiments include other fastening mechanisms.

[0088] FIG. 5 illustrates an example dentition coupling device 212. The dentition coupling device 212 is an embodiment of a dentition coupling device such as the dentition coupling device 124. The dentition coupling device 212 is configured to couple to a patient's dentition using temporary anchorage devices such as temporary anchorage devices 222a and 222b. The dentition coupling device 212 includes an arch portion 214 and securing regions 218a and 218b. The arch portion 214 is a rigid structure and may be shaped to fit along a surface of the patient's dentition. The arch portion 214 may be custom fabricated for a patient based on an impression of the patient's dentition or measurements of the patent's dentition. The arch portion 214 may include a contoured portion 216 that has a shape that matches the lingual/buccal (outer) surfaces of at least some of the patient's teeth. For example, the dentition coupling device 212 may be produced using rapid fabrication technology based on an impression of the patient's dentition. However, in some embodiments, the dentition coupling device 212 does not include a contoured portion (e.g., when a patient is completely or primarily edentulous).

[0089] In some embodiments, the securing regions 218a and 218b include surfaces that match the contour of portions of the patient's dentition (e.g., based on a previously captured impression of the patient's dentition). The securing regions may align with an edentulous region of the patient's dentition or another portion of the patient's dentition. Although the example shown in FIG. 5 includes two securing regions, the dentition coupling device 212 can include just one securing region or more than two securing regions.

[0090] The securing regions 218a and 218b include fastener receivers 220a and

220b respectively. The fastener receivers 220a and 220b are configured to receive a fastener such as the temporary anchorage devices 222a and 222b. In some embodiments, the fastener receivers 220a and 220b are apertures through which the bone penetrating portions of the temporary anchorage devices 222a and 222b may pass. The fastener receivers 220a and 220b may be sized so as to prevent the heads of the temporary anchorage devices 222a and 222b from passing. In this manner, the temporary anchorage devices 222a and 222b secure the dentition coupling device 212 to the patient's dentition.

[0091] Alternatively, the fastener receivers 220a and 220b include clasps to couple to the heads of temporary anchorage devices 222a and 222b. In these embodiments, the temporary anchorage devices 222a and 222b may be inserted into the patient's bone tissue before the dentition coupling device 212 is placed on the patient's dentition. Then, the dentition coupling device 212 can be placed on the patient's dentition so that the clasps couple with the heads of the already implanted temporary anchorage devices 222a and 222b.

[0092] In these embodiments, the temporary anchorage devices 222a and 222b may be placed in the patient's dentition. After the temporary anchorage devices 222a and 222b are placed, an impression of the patient's dentition can be captured. The dentition coupling device 212 can then be custom designed based on that impression to match at least a portion of the contour of the patient's dentition and to include clasps to mate with the implanted temporary anchorage devices 222a and 222b. The dentition coupling device 212 can then be fabricated using for example rapid fabrication technologies.

[0093] The temporary anchorage devices 222a and 222b are fastening devices formed from a biocompatible material (e.g., titanium) that are configured to penetrate through the patient's gum tissue and into the patient's bone tissue. The temporary anchorage devices 222a and 222b may include threads that are configured to secure the temporary anchorage devices 222a and 222b. The temporary anchorage devices 222a and 222b may include heads with various configurations. For example, the temporary anchorage devices 222a and 222b may include a receiver for a tightening tool. Additionally or alternatively, the temporary anchorage devices 222a and 222b may include a head with a spherical shape that can serve as a fiducial for determining the relationship between the dentition coupling device 212 and the patient's dentition. Alternatively, when the dentition coupling device 212 is custom fabricated to fit a particular patient's dentition, the relationship between the dentition coupling device 212 and the patient's dentition may be inferred.

[0094] FIG. 6 illustrates an embodiment of the patient assembly 104. The patient assembly 104 includes the clutch 160 and a reference structure 162. The reference structure 162 is an example of the reference structure 122. In this example, the components of the reference structure 162 are similar to previously described components of the clutch 160.

[0095] In this example, the reference structure 162 includes a dentition coupling framework 230, a framework 232, and fiducial markers 234a, 234b, 234c, 234d, 234e, and 234f (referred to collectively as fiducial markers 234). The dentition coupling framework 230 may be similar to the dentition coupling framework 170, the framework 232 may be similar to the framework 172, and the fiducial markers 234 may be similar to fiducial markers 174, each of which has been previously described with respect to at least FIG. 3.

[0096] In some embodiments, the reference structure 162 is coupled to the patient's dentition opposite to the clutch 160. In this manner, the positions of the fiducial markers 234 can be determined and used to determine the motion of the patient's dentition opposite the clutch 160. By determining the motion of the patient's dentition opposite of the clutch 160, the relative motion of the patient's lower dentition (i.e., mandible) can be determined relative to the patient's upper dentition (i.e., maxilla). Beneficially, by determining the relative motion, movements of the patient's head and neck can be ignored so that only jaw motion is captured.

[0097] FIG. 7 illustrates another embodiment of the patient assembly 104. In this embodiment, the patient assembly 104 includes the clutch 160 and a reference structure 250. The reference structure 250 is another example of the reference structure 122. In this example, the reference structure 250 includes the dentition coupling framework 230, a framework 252, and the fiducial markers 234.

[0098] The framework 252 is similar to the framework 232 except that the framework 252 includes arms directed dorsally (i.e., in towards the patient's face) rather than ventrally (i.e., out away from the patient's face). Beneficially, for some patient's dental anatomy and jaw motion, the dorsally oriented arms may lessen the likelihood that the clutch 160 and the reference structure 250 will make contact with one another and interfere with the patient's jaw motion. [0099] FIG. 8 illustrates another embodiment of the patient assembly 104. In this embodiment, the patient assembly 104 includes a clutch 270 and a reference structure 280. The clutch 270 is another example of the clutch 140, and the reference structure 280 is another example of the reference structure 122. In this example, the clutch 270 includes the dentition coupling framework 170, a framework 272, and the fiducial markers 174, while the reference structure 280 includes the dentition coupling framework 230, a framework 282, and the fiducial markers 234.

[0100] The framework 272 is similar to the framework 172, except that the framework 272 includes additional arms that extend out laterally to position the fiducial marker 174b and the fiducial marker 174f further away from the center of the framework 272. Similarly, the framework 282 is similar to the framework 252 except that the framework 282 also includes additional arms that extend out laterally to position the fiducial marker 234b and the fiducial marker 234e further away from the center of the framework 282. Beneficially, by positioning at least some of the fiducial markers 174 and fiducial markers 234 further away from the center, the framework 272 and framework 282 may be more sensitive to smaller changes to the orientation or position of the associated patient dentition.

[0101] FIG. 9 illustrates another embodiment of the patient assembly 104. In this embodiment, the patient assembly 104 includes the clutch 160 and a reference structure 300. The reference structure 300 is another example of the reference structure 122. In this example, the reference structure 300 includes the dentition coupling framework 230, a framework 302, and the fiducial markers 234.

[0102] The framework 302 is similar to the framework 232 except that one side of the framework 302 includes arms that position the fiducial marker 234a dorsally, the fiducial marker 234b ventrally, and the fiducial marker 234c superiorly (i.e., above the rest of the framework 302).

[0103] FIG. 10 illustrates another embodiment of the patient assembly 104. In this embodiment, the patient assembly 104 includes a clutch 322 and a reference structure 320. The clutch 322 is another example of the clutch 140, and the reference structure 320 is another example of the reference structure 122. In this example, the clutch 322 includes the dentition coupling framework 170, a framework 304, and the fiducial markers 174, while the reference structure 320 includes the dentition coupling framework 230, a framework 306, and the fiducial markers 234. [0104] The framework 304 is similar to the framework 172 except that framework includes only three arms, which are disposed so as to be in front of the patient's mouth rather than out to the sides of the patient's mouth when the dentition coupling framework is being worn. The framework 306 is similar to the framework 304 except that the arms are configured to position the fiducial markers 174a and 174c in opposite directions from the fiducial markers 234a and 234c, respectively, when both the clutch 322 and the reference structure 320 are worn by the patient.

[0105] The three fiducial markers 174 shown in FIG. 10 may be sufficient to determine the position and orientation of the clutch 322 from images so long as the positions of the fiducial markers 174 in the image can be determined (e.g., the fiducial markers 174 are not significantly occluded in the image). Similarly, the three fiducial markers 234 may be sufficient to determine the position and orientation of the reference structure 320 in similar circumstances. The orientation of the arms of the clutch 322 and the reference structure 320 may minimize the likelihood of physical interference or occlusion between the fiducial markers 174 and the fiducial markers 234. Beneficially, the embodiment shown in FIG. 10 may be of lighter weight than other embodiments due to having fewer fiducial markers and smaller frameworks.

[0106] FIG. 11 illustrates another embodiment of the patient assembly 104. In this embodiment, the patient assembly 104 includes the clutch 332 and a reference structure 330. The clutch 332 is another example of the clutch 140, and the reference structure 330 is another example of the reference structure 122. In this example, the clutch 332 includes the dentition coupling framework 170, a framework 350, and an orientation-indicating fiducial marker 354b, while the reference structure 330 includes the dentition coupling framework 230, a framework 352, and an

orientation-indicating fiducial marker 354a.

[0107] The framework 350 is similar to the framework 304 but lacks an arm structure and contains one orientation-indicating fiducial marker 354b instead of the multiple fiducial markers 174 attached to framework 304.

[0108] The framework 352 is similar to the framework 306 but lacks an arm structure and contains one orientation-indicating fiducial marker 354a instead of the multiple fiducial markers 174 attached to framework 306.

[0109] The orientation-indicating fiducial markers 354a and 354b (referred to collectively as orientation-indicating fiducial markers 354) contain a non-repeating surface design 356 that is usable to determine the orientation of the fiducial markers as described in detail with respect to FIG. 12. The orientation-indicating fiducial markers 354a and 354b may include surface designs that are the same as or different from one another.

[0110] FIG. 12 illustrates an embodiment of the orientation-indicating fiducial markers 354. An example embodiment of the surface design of the orientation- indicating fiducial markers 354 contains a non-repeating arrangement of design elements. In at least some aspects, the surface-design is an orientation-unique surface design. As used herein, an orientation-unique surface design is a surface design in which the surface design is different depending on the orientation from which the orientation-indicating fiducial markers 354 are viewed.

[0111] In one example orientation-unique surface design, the design elements comprise dots in a dot matrix that covers the surface of the orientation-indicating fiducial markers 354. The dots of the dot matrix are filled in (or left unfilled) in such a manner that a different arrangement of dots will be filled in any hemisphere of the fiducial marker. The surface design is not limited to dots, however, and can contain other design elements such as lines or any other shapes or symbols. The arrangement or orientation of the visible design elements may then be used to determine the orientation of the orientation-indicating fiducial markers 354.

[0112] In some embodiments, the cameras that are part of the imaging system 102 as described in FIG. 14 capture an image of the orientation-indicating fiducial markers 354. Unless the orientation-indicating fiducial markers 354 are occluded by another structure, the image will include the half of each of the orientation- indicating fiducial markers 354 that is facing the imaging system 102 (i.e., the image will include a hemisphere from each of the fiducial markers).

[0113] When the orientation-indicating fiducial markers 354 include an orientation-unique surface design, the surfaces captured in the image can be used to determine the orientations of the orientation-indicating fiducial markers 354. For example, a database can store a plurality of surface images, each of which is associated with a particular orientation. A surface image that is captured can then be compared to the surface images in the database to determine the orientation. If the captured surface image substantially matches an image from the database (e.g., the differences between the images are below a threshold), the orientation associated with the substantially matching image in the database can be used. If the captured surface image does not substantially match an image from the database, the orientation may be determined by interpolating between the orientations associated with a plurality of images in the database which have been identified as being most similar to the captured image. In some embodiments, the interpolation is based on weighting the images from the database based on the similarity to the captured image.

[0114] In an alternate embodiment, the images of the orientation-indicating fiducial markers 354 can be analyzed to determine the orientation of the orientation- indicating fiducial markers 354 based on landmarks (i.e., specific recognizable design elements) within the surface design and the relative position of those landmarks with respect to each other.

[0115] Additionally, some embodiments do not include a surface design that is necessarily an orientation-unique surface design. In these embodiments, the surface design may still be unique locally. For example, if the orientation changes in a small manner, the visible portion of the surface design will be changed as well. Thus, the surface design can be used to determine the relative change in orientation between two images of the surface even if an absolute orientation cannot be determined. In some embodiments, an initial image is captured using the imaging system 102 to determine reference orientations of the orientation-indicating fiducial markers 354. Then, a series of images (e.g., a video) is captured as the orientation of the orientation-indicating fiducial markers 354 changes. The relative changes in the orientation between each pair of consecutively captured images can then be determined. In this manner, the changes to the orientation of the clutch 332 relative to the reference structure 330 can be determined as the patient's jaw moves.

[0116] FIG. 13 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, a light source assembly 404, and an extension member 408. The dentition coupling device 402 is an example of the dentition coupling device 124, the extension member 408 is an example of the framework 126, and the light source assembly 404 is an example of the position indicator system 128.

[0117] The light source assembly 404 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.

[0118] In some embodiments, the light source assembly 404 comprises a first, second, and third light source. The first and second light sources may emit substantially collimated light in parallel but opposite directions such as to the left and right of the patient when the clutch 400 is coupled to the patient's dentition. The third light source may emit substantially collimated light in a direction that is perpendicular to the first and second light sources, such as toward the direction the patient is facing. Alternatively, some embodiments of the light source assembly 148, 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.

[0119] In the example of FIG. 13, the light source assembly 404 includes light emitters 406a, 406b, and 406c (referred to collectively as light emitters 406) and a housing 410. The light emitter 406a is emitting a light beam LI, the light emitter 406b is emitting a light beam L2, and the light emitter 406c is emitting a light beam L3. The light beams LI and L2 are parallel to each other, but directed in opposite directions. The light beam L3 is perpendicular to the light beams LI and L2. In at least some embodiments, the housing 410 is configured to position the light emitters 406 so that the light beams LI, L2, and L3 are approximately co-planar with the occlusal plane of the patient's dentition.

[0120] 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.

[0121] In the example of FIG. 13, the dentition coupling device 402 is rigidly coupled to the light source assembly 404 by the extension member 408. The extension member 408 extends from the dentition coupling device 402 and is configured to extend out of the patient's mouth when the dentition coupling device

402 is worn on the patient'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.

[0122] FIG. 14 illustrates a top view of an embodiment of a reference structure 430 and an embodiment of an imaging system 432. The reference structure 430 is an example of the reference structure 122. The imaging system 432 is an example of the imaging system 102.

[0123] The reference structure 430 may be similar to the clutch 400, except that the reference structure 430 is configured to be worn on the opposite arch from the clutch 400. The reference structure 430 includes a dentition coupling device 434, and extension member 44, and a light source assembly 442. The dentition coupling device 434 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 extension member 440 is an example of the framework 132 and the light source assembly 442 is an example of the position indicator system 134.

[0124] The dentition coupling device 434 is configured to removably couple to the dentition of the patient. The dentition coupling device 434 is coupled to the opposite arch of the patient's dentition as the clutch (e.g., the dentition coupling device 434 couples to the maxillary arch when the clutch 400 is coupled to the mandibular arch). In some embodiments, the dentition coupling device 434 is coupled to the extension member 440 that is configured to extend out through the patient's mouth when the dentition coupling device 434 is coupled to the patient's dentition. The extension member 440 may be similar to the extension member 408.

[0125] In the embodiment shown, the extension member 440 is rigidly coupled to a light source assembly 442. The light source assembly 442 may be permanently coupled to the extension member 440. In other embodiments, the extension member 440 is configured to removably couple to the light source assembly 442. For example, the extension member 440 may couple to the light source assembly 442 via a thumb screw or another type of fastener. [0126] The imaging system 432 includes a screen framework 436, screens 438a, 438b, and 438c (referred to collectively as screens 438), and cameras 420a, 420b, and 420c (referred to collectively as cameras 420).

[0127] The screen framework 436 is a structure that positions the screens 438 to surround a patient's mouth so that light emitted by the reference structure 430 or a clutch (not shown) worn by the patient will intersect with the screens 438. Although alternatives are possible, the screen framework 436 may be U-shaped, having one side for each of the screens 438. In this example, the screen framework 436 orients the screen 438c at a right angle from screen 438a and at a right angle from screen 438b. In some embodiments, the screen framework 436 is configured to connect to the top of the screens 438 (e.g., if the screens 438 are formed from a rigid material). Alternatively, the framework may partially or fully surround the screens 438 (e.g., if the screens 438 are formed from a flexible material).

[0128] Other embodiments may include different numbers of the screens 438 and different arrangements of the light source assembly 442. For example, some embodiments may include two light emitters and two screens. One of the screens may be disposed in front of the patient (i.e., in the anterior direction) and one may disposed on one side of the patient (i.e., in a lateral direction). Additionally, some embodiments may include a third light source that emits light up or down (i.e., in the superior or inferior direction).

[0129] The screens 438 may be formed from a translucent material so that the points where the light beams emitted by the light source assembly 442 intersect with the screens 438 may be viewed from outside of the screens 438. Images that include these points of intersection may be recorded by the imaging system 102. The motion determining device 106 may then analyze these captured images to determine the points of intersection of the light beams with the screens 438 to determine the location of the light source assembly 442. The position of the light source assembly 404 of the clutch 400 (not shown) may be determined in a similar manner.

[0130] The cameras 420 are positioned and oriented to capture images of the screens 438. For example, the camera 420a is positioned and oriented to capture images of the screen 438a, the camera 420b is positioned and oriented to capture images of the screen 438b, and the camera 420c is positioned and oriented to capture images of the screen 438c. In some embodiments, the cameras 420 are mounted to the screen framework 436 so that they move with the screen framework 436. For example, each of the cameras 420 may be coupled to the screen framework 436 by a camera mounting assembly such as is shown in FIG. 17. In this manner, the position and orientation of the cameras 420 relative to the screens 438 does not change if the screen framework 436 is moved.

[0131] The cameras 420 may store a series of images or transmit images as the images are captured to a storage device or a computing device such as the motion determining device 106. In some embodiments, the cameras 420 transmit images over a wired network. In other embodiments, the cameras 420 transmit images over a wireless network.

[0132] The system 100 may include techniques to compensate for variations in the alignment of the cameras to the screens or the screens to one another. For example, a calibration pattern of known shape and dimensions may be projected onto the screens and captured with the cameras. The recorded images may be analyzed to identify deviations from the known shape and dimensions. A translation can then be generated to translate the captured image to the expected shape and dimensions. This is one example of a method to compensate for variations in alignment; other methods are used in other embodiments. Similar methods can be used to compensate for variations in the relative positions of the screens (e.g., by projecting a pattern of known relation on multiple screens). In one example, light that is expected to be collinear is projected on multiple screen simultaneously. Any deviations in the collinearity of the light in the captured images can then be compensated (e.g., using a transformation). Similar techniques can also be used to compensate for field of view distortion in the cameras.

[0133] FIG. 15 illustrates an embodiment of the patient assembly 460. The patient assembly 460 is an example of the patient assembly 104. The patient assembly 460 includes a clutch 462 and a reference structure 464.

[0134] The clutch 462 may be similar to the clutch 400. However, the clutch 462 includes a plurality of internal fiducial markers 466. The internal fiducial markers 466 are usable to establish a static relationship between the clutch and the patient's dentition. The internal fiducial markers 466 may be similar to the internal fiducial markers 206. Additionally, the internal fiducial markers 466 may be used to establish a static relationship between a dentition coupling device of the clutch 462 and a light source assembly of the clutch 462. Various embodiments include various numbers of the internal fiducial markers 466. [0135] The reference structure 464 may be similar to the reference structure 430. However, the reference structure 464 includes internal fiducial markers 468 that are usable to establish a static relationship between the reference structure 464 and the patient's dentition. The internal fiducial markers 468 may be similar to the internal fiducial markers 206. Various embodiments include various numbers of the internal fiducial markers 468.

[0136] Additionally, the reference structure 464 includes the light source assembly 442. The light source assembly 442 includes light emitters 472a, 472b, and 472c that emit light beams L4, L5, and L6. Similar to the light beams LI, L2, and L3 emitted by the clutch 462, the light beams L4, L5, and L6 are directed to intersect with screens (not shown) such as the screens 438.

[0137] The light beams L4, L5, and L6 may have a different color (i.e., have a different wavelength) than the light beams LI, L2, and L3. In this manner, the motion determining device 106 can distinguish the light beams LI, L2, and L3 from the light beams L4, L5, and L6 so that the relative positions of the light source assemblies on the clutch 462 and the reference structure 464.

[0138] Additionally or alternatively, the light source assembly 442 of the reference structure 464 and the light source assembly 404 of the clutch 462 may strobe on and off in a synchronized manner so that the motion determining device 106 may determine which points on the images of the screens 438 (not shown) correspond to the light source assembly 442 from the reference structure 464 and which correspond to the light source assembly 404 of the clutch 462. For example, the imaging system 102 may capture sequential frames of images, while the light source assembly on the clutch 462 may be activated during odd frames and the light source assembly on the reference structure 464 may be activated during even frames (or vice versa). As another example, one of the light source assemblies may strobe, while the other does not, or both may strobe but at different frequencies or with different patterns. Another alternative is that the light beams emitted from the reference structure 464 are distinguished from the light beams emitted by the clutch 462 based on position (e.g., the beams that are higher may be determined to be emitted by the reference structure 464 as it is configured to attach to the upper arch).

[0139] FIG. 16 illustrates an embodiment of a light source assembly 510 that uses a single laser source. The light source assembly 510 may be similar to the previously described light source assemblies such as the light source assembly 404. The light source assembly 510 emits three laser beams LI, L2, and L3 from a single laser emitter 516.

[0140] The light source assembly includes a housing 512, fiducial markers 514, the laser emitter 516, and a beam splitter assembly 518.

[0141] The housing 512 surrounds the light source assembly 510 and beam splitter assembly 518. The housing 512 may contain one or more apertures through which light may be emitted by the light source assembly 510. In some embodiments, the housing 512 is formed from a rigid or semi-rigid material, such as plastic, metal, ceramic, or a composite material. In some embodiments the housing 512 may be a single integral component. Alternatively, the housing 512 may include a coupling structure configured to removably couple together the multiple components of the housing. In some embodiments, the top component of the housing 512 includes a connector that is configured to mate with a connector on the bottom component of the housing 512. The components of the housing may also include holes or receivers for screws or other fasteners to couple the components together.

[0142] The light source assembly 510 also includes one or more fiducial markers 514 disposed on a surface of the housing 512 that can be used to establish the position of the light source assembly 510 relative to a clutch such as the clutch 400 or a reference structure such as the reference structure 430. Some embodiments do not include fiducial markers and the relationship between the light source assembly 510 and the clutch or reference structure is established in advance such as when the light source assembly is 510 is permanently coupled to the clutch or reference structure. The relationship may be established based on the design of the clutch or reference structure. To address potential manufacturing variances, the clutch or the reference structure may be characterized using a touch probe or similar device.

[0143] In the example of FIG. 16, the light source assembly 510 includes a single laser emitter 516. Although alternatives are possible, the laser emitter 516 may be a semiconductor laser emitter such as a laser diode emitters or a solid-state laser emitter such as diode-pumped solid state laser emitter. The laser emitter 516 emits a beam of collimated light into the beam splitter assembly 518.

[0144] The beam splitter assembly splits the laser beam emitted by the laser emitter 516 into three separate light beams LI, L2, and L3. In some embodiments, the beam splitter assembly 518 contains three reflector surfaces 520, 526, and 528 and two beam splitters 522 and 524. In this example, the collimated light from the laser emitter 516 is initially emitted as a vertical light beam on to the first reflector surface 520. The vertical light beam is then reflected by the first reflector surface 520 to form a horizontal light beam. In some embodiments, the laser emitter 516 is orientated to emit the light beam horizontally and the first reflector surface 520 is omitted.

[0145] This horizontal light beam then passes through the first beam splitter 522. The first beam splitter 522 splits the horizontal light beam into two light beams that are substantially orthogonal to one another. One of the light beams is emitted out of the housing of the light source assembly 510 as light beam LI, while the other light beam continues in a direction that is the same as or similar to the direction of the horizontal light beam.

[0146] The horizontal light beam continues on until it reaches the second beam splitter 524. The second beam splitter 524 again splits the horizontal light beam into two light beams that are substantially orthogonal to one another. One of the light beams continues in the same direction as the incoming horizontal light beam and is emitted out of the housing of the light source assembly 510 as light beam L3. The other light beam travels in a direction that is substantially orthogonal to the light beam L3 and opposite the light beam LI . This light beam continues until it reaches the second reflector surface 526. The second reflector surface 526 reflects the light beam orthogonally such that it travels in the opposite direction as light beam L3 until reaching the third reflector surface 528. The third reflector surface 528 once again reflects the light beam orthogonally to produce the light beam L2 travelling in a direction that is substantially opposite to but collinear with the light beam LI . The reflected light beam is emitted out of the housing of the light source assembly 510 as light beam L2. In some aspects, the second beam splitter 524, the second reflector surface 526, and the third reflector surface 528 are disposed so as to cause the light beam LI and the light beam L2 to be collinear.

[0147] In some embodiments, the light beams LI and L2 are substantially parallel to each other, but directed in opposite directions, and the light beam L3 is substantially perpendicular to the light beams LI and L2. Further, in some embodiments, the light beams LI and L2 are collinear. In at least some

embodiments, the light source assembly 510 is configured to position the laser emitter 516 so that the light beams LI, L2, and L3 are approximately co-planar with the occlusal plane of the patient's dentition. [0148] Alternatively, some embodiments, are configured so that the light beams LI and L2 are not collinear when emitted. These embodiments, may omit the second reflector surface 526 and the third reflector surface 528.

[0149] FIG. 17 illustrates an embodiment of an imaging system 530. The imaging system 530 is another example of the imaging system 102.

[0150] This example embodiment of the imaging system 530 includes the cameras 420a, 420b and 420c, a stand 532, camera mounting assemblies 534a, 534b, and 534c. The imaging system 530 also includes the screen framework 436, and the screens 438a, 438b, and 438c.

[0151] The stand 532 is a structure that positions the imaging system for use in capturing movement of a clutch and reference structure in a patient's mouth. The stand 532 includes legs 536a, 536b, 536c, 536d (referred to collectively as legs 536) and mounting framework 538.

[0152] The legs vertically position the mounting framework 538. Some embodiments of the stand 532 are designed to be placed on the floor and the legs 536 have a longer length. Other embodiments of the stand 532 are designed to be placed on an elevated surface such as a countertop or table top and the legs 536 have a shorter length. The length of the legs 536 may be fixed or adjustable.

[0153] The mounting framework 538 is a structure that other components of the imaging system 530 are mounted to. In some embodiments, the mounting framework 538 comprises a plurality of horizontally oriented elongate members. In other embodiments, the mounting framework 538 may include a surface as well. As shown in FIG. 17, the camera mounting assemblies 534 and the stand framework are mounted to the mounting framework 538.

[0154] The camera mounting assemblies 534 are assemblies that position and orient the cameras 420 relative to the screens 438. The camera mounting assemblies 534 may include various components to adjust the position and orientation of the cameras 420. In at least some embodiments, the position of the cameras 420 on the camera mounting assemblies 534 is selected so that the field of view of the cameras 420 approximately coincides with the screens 438. Alternatively, the field of view of the cameras 420 may approximately coincide with a portion of the screen in which the light emitted by a clutch device would be likely to intersect.

[0155] For purposes of explanation, the camera mounting assembly 534b is described in greater detail herein. This discussion is equally applicable to the camera mounting assemblies 534a and 534b. The camera mounting assembly 534b includes a sliding rail 540 and a vertical positioning system 542.

[0156] The sliding rail 540 is mounted to the mounting framework 538 below the screen 438b. The sliding rail 540 extends away from the screen 438b in a direction that is approximately normal to the surface of the screen 438b. The sliding rail 540 includes a channel and a sliding element to which the bottom end of the vertical positioning system 542 is connected. The sliding element can slide through the channel to adjust the distance of the camera 420b from the screen 438b. The sliding rail 540 also includes a locking mechanism, which when engaged prevents the sliding element from moving through the channel.

[0157] The vertical positioning system 542 is mounted to the movable element on one end and the camera 420b on the other. The vertical positioning system 542 is a structure that vertically positions the camera 420b. In some embodiments, the height of the vertical positioning system 542 is adjustable. For example, the vertical positioning system 542 may include a telescoping component that slides up and down to adjust the height of the vertical positioning system 542. The vertical positioning system 542 may also include a locking component that prevents the telescoping element from moving so as to lock the height of the vertical positioning system 542.

[0158] FIG. 18 illustrates a perspective view of the clutch 400 disposed within the screens 438 of the imaging system. In this example, the screen 438c is shown as transparent so that the clutch 400 can be seen.

[0159] In this example, the light emitter 406a is emitting a light beam LI, which intersects with the screen 438a at intersection point II; the light emitter 406b is emitting a light beam L2, which intersects with the screen 438b at intersection point 12; and the light emitter 406c is emitting a light beam L3, which intersects with the screen 438c at intersection point 13. As the position and orientation of the clutch 400 changes relative to the screens 438, the location of at least some of the intersection points II, 12, and 13 will change as well.

[0160] The camera 420c captures an image of the screen 438c, including the intersection point 13 of the light beam L3 emitted by the light emitter 406c. The camera 420c may capture a video stream of these images. Similarly, although not shown in this illustration, cameras 420a and 420b capture images of the screens 438a and 438b and the intersection points II and 12. [0161] The captured images from the cameras 420 are then transmitted to the motion determining device 106. The motion determining device 106 may determine the location of the intersection points II, 12 and 13, and from those points the location of the light source assembly 404. In some embodiments, a point of common origin within the light source assembly 404 for the light beams LI, L2, and L3 is determined based on the location of the intersection points II, 12, and 13 (e.g., the point at which the light beams intersect). Based on the determined locations of the light beams, the location and orientation of the clutch 400 relative to the screens 438 can be determined.

[0162] In other embodiments, the motion determining device 106 fits the intersection points II, 12, and 13 to a plane. The motion determining device 106 then determines the location of the light source assembly 404 by finding an intersection point of the light beam L3 with either of light beams L2 or L3.

[0163] FIG. 19 illustrates a perspective view of a reference structure 560. The reference structure 560 is configured to mount to an imaging system such as the imaging system 102. In some embodiments, the imaging system 102 is supported by and moves with the reference structure 560. In other embodiments, the imaging system 102 secures the reference structure 560 so that the reference structure 560 cannot move and consequently the patient's upper jaw and head cannot move.

[0164] The reference structure 560 includes the dentition coupling device 434, the extension member 440, a housing 562, and a framework mounting assembly 564. The housing 562 is a structure that includes a connector for connecting with the framework mounting assembly 564. The housing 562 may include features such as notches or ridges that operate to ensure that the connection to the framework mounting assembly 564 is repeatable and consistent (e.g., when connected the relative orientation and position of the housing 562 and framework mounting assembly 564 are always substantially the same). In some embodiments, the housing 562 is formed from a rigid or semi-rigid material, such as plastic, metal, ceramic, or a composite material. In some embodiments the housing 562 and the dentition coupling device 434 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).

Alternatively, the housing 562 may include a connector for establishing a consistent and repeatable connection with the extension member 440. Although not shown in FIG. 19, some embodiments of the housing 562 house a light source assembly such as the light source assembly 442 or other components as well.

[0165] In the embodiment shown, the framework mounting assembly 564 includes a framework mounting post 566. The framework mounting post 566 is a post that extends from the housing 562 approximately vertically up above a patient's mouth when the reference structure 560 is being worn by the patient. The framework mounting post 566 is configured to connect to the screen framework as shown in FIG. 20.

[0166] FIG. 20 illustrates a top view of an embodiment of the reference structure 560 mounted to an imaging system 570. The imaging system 570 is another example of the imaging system 102.

[0167] The reference structure 560 is mounted to the imaging system 570 with the framework mounting assembly 564. In the embodiment shown, the framework mounting assembly 564 includes the framework mounting post 566 and a framework mounting extension member 568. The framework mounting assembly 564 is a rigid structure that operates to couple the screen framework 436 to the dentition coupling device 434. The framework mounting extension member 568 is joined to an end of the framework mounting post 566 that is opposite of the dentition coupling device 434. The framework mounting extension member 568 extends horizontally out away from the patient's mouth when the reference structure 560 is being worn by the patient.

[0168] The framework mounting extension member 568 may have different sizes in various embodiments as well and the size may depend on the size of the screens 438. For example, the framework mounting extension member 568 may have a length that positions the horizontal center of screens 438a and 438b to approximately line up with the patient's lips. In this manner, the framework mounting assembly 564 serves to help ensure the patient stays approximately centered in the screens during measurement operations.

[0169] FIG. 21 illustrates a perspective view of part of the reference structure 560 and part of the imaging system 570.

[0170] The reference structure 560 includes a dentition coupling device 434. The dentition coupling device 434, the screen framework 436, the screens 438, the framework mounting assembly 564, the framework mounting post 566 and the framework mounting extension member 568 are similar to the examples previously described.

[0171] The framework mounting extension member 568 is attached to the screen framework 436. A camera mounting assembly 480 is also attached to the screen framework 436. The camera mounting assembly 480 includes a camera mounting extension member 574 and a camera mounting post 576. The camera mounting extension member 574 couples to the screen framework 436 and extends to position the camera 420c out away from the patient. The length of the camera mounting extension member 574 varies in various embodiments and depends on the size of the screen 438c and the angle of view of the camera 420c. In at least some

embodiments, the length of the bracket is selected to position the camera 420c so that the field of view of the camera 420c approximately coincides with the screen 438c. Alternatively, the field of view of the camera 420c may approximately coincide with a portion of the screen in which the light emitted by a clutch device would be likely to intersect.

[0172] FIG. 22 illustrates an embodiment of a head-mounted patient assembly and imaging system 600. The head-mounted patient assembly and imaging system 600 includes a head-mounted patient assembly 602 and a head-mounted imaging system 604. The head-mounted patient assembly 602 is an example of the patient assembly 104 and the head-mounted imaging system 604 is an example of the imaging system 102. The head-mounted patient assembly 602 and the head-mounted imaging system 604 are connected together at joints 606a and 606b (collectively referred to as joints 606).

[0173] The joints 606 allow for a rotational coupling between the head-mounted patient assembly 602 and the head-mounted imaging system 604. The joints 606 include orientation-indicating fiducial markers 618. The orientation-indicating fiducial markers 618 may be fixedly connected to the head-mounted patient assembly 602. Fixedly connected means that the connection does not allow for relative movement of any sort, including rotation, between the connected components. The orientation-indicating fiducial markers 618 may be similar to the orientation-indicating fiducial markers 354, which are illustrated and described with respect to at least FIG. 11. An example of the joints 606 is illustrated and described with respect to at least FIG. 24. [0174] The head-mounted patient assembly 602 includes clutch arms 612a and 612b (referred to collectively as clutch arms 612). The clutch arms 612 are fixedly connected to the orientation-indicating fiducial markers 618 on one end. The other end of the clutch arms 612 are fixedly connected to a clutch dentition coupling device such as the dentition coupling device 124. As the dentition coupling device moves, the orientation-indicating fiducial markers 618 are moved or rotated as well by the clutch arms 612.

[0175] The head-mounted imaging system 604 includes a head mount 610 that is configured to fit on a patient's head, two camera assemblies 616a and 616b

(collectively referred to as camera assemblies 616), and condyle pins 622a and 622b (collectively referred to as condyle pins 622).

[0176] In one embodiment of the head mount 610, the structure of the head mount 610 is curved such that it fits the curve of the patient's head such that ends of the head mount 610 are on either side of the patient's head.

[0177] The camera assemblies 616 are attached to the head mount 610 on the vertical portions of both sides of the head mount 610. The camera assemblies 616 are configured to hold cameras in an orientation to capture images of the orientation- indicating fiducial markers 618 of the joints 606. In some embodiments, the camera assemblies 616 include cameras. The images captured by the camera are used to determine the orientation (either absolute or relative to a previous image) of the orientation-indicating fiducial markers 618, which can then be used to determine the orientation of the clutch arms 612 and the clutch and patient dentition attached thereto.

[0178] The condyle pins 622 are configured for use in aligning the joints 606 with a patient's condyle. When mounted on a patient, the condyle pins 622 should be located substantially at the location of the condyle. The condyle pins 622 may have a rounded tip and be made of a plastic or rubber material that will minimize patient discomfort when the condyle pins 622 contact the patient's skin.

[0179] When the condyle pins 622 are aligned with the patient's condyle, the joints 606 will also be aligned with the patient's condyle. By positioning the joints

606 in this manner, more of the patient's jaw movement may be reflected as rotations of the orientation-indicating fiducial markers 618.

[0180] FIG. 23 illustrates an embodiment of a head-mounted patient assembly and imaging system 630. The head-mounted patient assembly and imaging system 630 includes the head-mounted patient assembly 602 and a head-mounted imaging system 634. The head-mounted imaging system 634 is similar to the head-mounted imaging system 604 except that the head-mounted imaging system 634 includes reference arms 614 that are fixedly coupled to the head mount 610 on one end. On the other end, the reference arms 614 connect to a reference dentition coupling device such as the dentition coupling device 130. Due to the rigid connection to the patient's maxilla via the reference dentition coupling device, the reference arms 614 may stabilize that head-mounted imaging system 634 from skin and muscle movement associated with jaw motion.

[0181] FIG. 24 includes a detailed illustration of a joint 650. The joint 650 is an example of the joints 606. The joint includes the orientation-indicating fiducial marker 618b and mounting base 654. The mounting base 654 is connected to the head mount 610. The orientation-indicating fiducial marker 618b is hollow and includes a socket 652. The socket 652 is configured to mount on the mounting base 654 and rotate freely thereon.

[0182] FIG. 25 is a top-view of an embodiment of the head-mounted patient assembly and imaging system 630. In this view, the apertures 702a and 702b (collectively referred to as apertures 702) of the camera assemblies 616 can be seen. In some embodiments, cameras are mounted within or on top of the camera assemblies 616 to capture images through the aperture 702. The images will include a circular portion of the orientation-indicating fiducial markers 618 that can be used to determine the orientation of the orientation-indicating fiducial markers 618 and the clutch arms 612 connected thereto.

[0183] FIG. 26 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 dental appliance 824 or provide dental therapy. In this example, the system 800 includes a dental office 802 and a dental lab 804.

[0184] 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 comprises 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.

[0185] 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 the impression device 200 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.

[0186] 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.

[0187] 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 station generates motion data 810.

[0188] In other 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 image 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. Other embodiments of the motion data 810 are possible as well.

[0189] In some embodiments, still images are captured of the patient'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'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.

[0190] 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, 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.

[0191] 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.

[0192] The design system 816 is a system that is configured to generate the dental appliance data 818. In some embodiments, the dental appliance data 818 is three-dimensional digital data that represents the dental appliance component 820 and is in a format suitable for fabrication using the rapid fabrication machine 819.

[0193] In some embodiments, the design system 816 comprises a computing device including user input devices. In some embodiments, the design system 816 includes computer-aided-design (CAD) software that generates a graphical display of the dental appliance data 818 and allows an operator to interact with and manipulate the dental appliance data 818. In some embodiments, the design system 816 comprises 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's dentition according to the motion data 810 (which may be similar to a physical articulator). Additionally, in some embodiments, the design system 816 comprises a server that partially or fully automates the generation of designs of the dental appliance data 818, which may use the motion data 810.

[0194] The 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 appliances and/or dental treatments. This may be particularly beneficial in designing complex appliances and planning complex dental treatments such as implant supported denture systems.

[0195] 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, South Carolina. 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. [0196] Additionally, in some embodiments, the rapid fabrication machine 819 is configured to use the dental appliance data 818 to fabricate the dental appliance component 820. In some embodiments, the dental appliance component 820 is a physical component that is configured to be used as part or all of the dental appliance 824. For example, in some embodiments, the dental restoration component is milled from zirconium or another material that is used directly as a dental restoration. In other embodiments, the dental appliance component 820 is a mold formed from wax or another material and is configured to be used indirectly (e.g., through a lost wax casting or ceramic pressing process) to fabricate the dental appliance 824. Further, in some embodiments, the dental appliance component 820 is formed using laser sintering technology.

[0197] In some embodiments, the appliance fabrication station 822 operates to fabricate a dental appliance 824 for the patient. In some embodiments, the appliance fabrication station 822 uses the dental appliance component 820 produced by the rapid fabrication machine 819. In some embodiments, the dental appliance 824 is a filling, partial crown, full crown, veneer, bridge, complete denture, partial denture, implant framework, surgical splint, implant guide, or orthotic splints such as deprogramming splints and temporomandibular disorder (TMD) splints. For example, the implant frameworks may support complete or partial dentures and may be designed using implant framework design software applications. Other embodiments of the dental appliance 824 are possible as well. In some

embodiments, the dental appliance 824 is formed a from an acrylic, ceramic, or metallic material. In some embodiments, the dental impression 808 is used in the fabrication of the dental appliance 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 comprises equipment and process 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.

[0198] In some embodiments, the dental appliance 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 dental appliance 824 is properly defined by instructing the patient to engage in various bites. Additionally, in some embodiments, the dentist D uses the dental appliance 824 to provide a dental therapy such as orthognathic surgery or placement of one or more dental implants.

[0199] Additionally, in some embodiments, the dental office 802 is connected to the dental lab 804 via a network.

[0200] 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.

[0201] 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.

[0202] FIG. 27 is an example process 850 for designing a dental appliance or treatment based on captured jaw motion. In some embodiments, the process 850 is performed by the system 800.

[0203] At operation 852, an initial impression of a patient is acquired. In some aspects, the initial impression is captured using a digital or physical impressioning technique. Alternatively, the initial impression is acquired from a storage location such as a database that stores dental impression data (e.g., from a previous patient visit).

[0204] At operation 854, the patient assembly 104 is attached to the patient. As has been described previously, the patient assembly 104 may be attached to the patient's upper and lower dentition so as to capture relative jaw motion.

[0205] At operation 856, a second impression of the patient is captured while the patient assembly 104 is attached to the patient. As has been described previously, the patient assembly may include various internal markers the location of which may be captured in the second impression. The patient does not necessarily wear the entire patient assembly during this operation. For example, the patient may wear the dentition coupling device of the clutch and the dentition coupling device of the reference structure for the second impression.

[0206] At operation 858, the initial impression and the second impression are aligned with one another. Various techniques may be used to align the impressions. In some embodiments, the shape or approximate shape of the attached patient assembly is subtracted from the second impression before performing the alignment. Boolean operations may be used to subtract the shape of the attached patient assembly. The positon of the patient assembly in the second impression may be determined based on the location of the fiducials in the second impression.

[0207] At operation 860, a static relationship between the patient assembly and the patient's dentition is determined. In some embodiments, the static relationship is determined based on the alignment of the initial impression to the second

impression. Alternatively or additionally, the static relationship may be determined based on the design of the patient assembly. For example, in some embodiments, the patient assembly 104 is custom fabricated to fit a patient's dentition in a particular manner. In these embodiments, when the patient assembly 104 is properly attached to the patient's dentition, the static relationship between the patient assembly and the patient's dentition can be determined based on that design. In these embodiments, it may not be necessary to capture an impression of the patient with the patient assembly attached. Additionally, in some embodiments, the static relationship between the patient assembly and the patient's dentition is determined later in the process 850 such as by capturing images of the inside of the impression device 200 after the patient assembly has been removed from the patient.

[0208] At operation 862, images are captured while the patient's mandible moves. In some embodiments, the patient's mandible is first moved in a hinge motion (e.g., opened straight up) one or more times. The patient may move his or her jaw in accord with directions from the dentist. Additionally or alternatively, the dentist may move the patient's jaw. Based on the motion data captured by the patient, the location of the screw axis of the temporomandibular joint may be determined.

[0209] In some embodiments, images are also captured while the patient's mandible is moved excursively and protrusively. Additionally, in some embodiments, images are captured while the patient engages in a chewing motion such as by chewing on a bolus of wax or a similar substance. In this manner, images are captured throughout a range of patient mandibular movements.

[0210] At operation 864, the movement of the patient's mandible is determined based on the captured images. In some embodiments, the movement of the patient's mandible is determined by analyzing the captured images to determine the location of intersection points on screens in the images. Based on the determined locations of the intersection points, the relative positions and orientation of portions of the patient assembly can be determined. Using the determined static relationship between the patient assembly 104 and the patient's dentition the position and orientation of the patient's dentition can be determined in each of the images (or sets of simultaneously captured images). Based on multiple images, the motion of the patient's mandible relative to the maxilla can be determined.

[0211] Alternatively, the movement of the patient's mandible is determined based on determining the location or orientation of one or more fiducial markers attached to the patient assembly.

[0212] At operation 866, a dental appliance is designed or a dental treatment is planned based on digitally simulating the movement of the patient's mandible.

[0213] If desired, condyle displacement can be determined and analyzed during post processing by receiving or inferring the condyle locations relative to the patient's dentition and applying the recorded motion transformations to those condyle locations. These locations may be received via user input in a user interface. The user input may be based on clinical physical measurements. These locations may also be determined by integrating three-dimensional images of at least a portion of the patient's craniofacial anatomy that includes the condyles with the three- dimensional image of the patient's dentition.

[0214] The three-dimensional images of the patient's craniofacial anatomy may include a combination of three-dimensional surface scans of the patient's dentition, computed tomography (CT) data, cone beam computed tomography (CBCT) data, and three-dimensional photos. These three dimensional images of the patient's craniofacial anatomy may be aligned relative to one another and the three- dimensional images of the patient's dentition by matching common surfaces that are common to multiple images. Additionally, the approximate condyle locations may be inferred based on the recorded motion when the jaw is opened and closed. [0215] In some aspects, CBCT or CT data is captured while the patient is wearing a device that includes one or more fiducial markers. For example, the CBCT or CT data may be captured while the patient is wearing the impression device 200 (illustrated in FIG. 4) or the clutch 462 (illustrated in FIG. 15). The CBCT or CT data can then be converted to a mesh using an appropriate mesh creation algorithm such as the marching cubes algorithm. This mesh from the CBCT or CT data can then be aligned with a mesh representing an impression of the patient while the patient is wearing the impression device 200. These two meshes can be aligned using various techniques such as an iterative closest point alignment technique. Once aligned, the motion data captured while the patient was wearing the impression device 200 can be applied to the mesh of the CBCT or CT data. In this manner, the movement of the condyle can be visualized in the condyle. The combined movement data and CBCT or CT data can be used to, for example, plan implant treatments and evaluate various other types of restorations. In some embodiments, one an implant is positioned relative to the CBCT or CT data, the implant can move with the CBCT or CT data.

[0216] Although the process 850 determines the static relationship between the patient assembly and the patient's dentition before capturing images while the patient's jaw in motion, other embodiments determine the static relationship at another point in time such as after capturing images of the patient' s j aw is in motion.

[0217] FIG. 28 is an example process 900 for determining the relative motion of the patient's upper and lower dentition based on images captured by the imaging system 102. In some embodiments, the process 900 is performed by the motion determining device 106.

[0218] At operation 902, image sets of the patient assembly attached to a patient's dentition captured while the patient's dentition moves are received. In some embodiments, each of the image sets comprises a single image. In other embodiments, each of the image sets comprises multiple images that were captured simultaneously (e.g., at the same or approximately the same time) by different cameras.

[0219] At operation 904, a loop processes each of the received image sets.

Within this description of the loop of operation 904, the received image set that is being processed is referred to as the current image set. [0220] At operation 906, the positions of the position indicators are determined by processing the images in the current image set. In some embodiments, image processing techniques are used to identify the location within the image of some or all of the fiducial markers. Then based on one or more of the position and size of the fiducial marker within the image, the three-dimensional position of the fiducial marker is determined. When an image set includes multiple images captured from different cameras disposed to captured images of the patient assembly from a different angle, the positions of the fiducial markers in the different images may be correlated to determine the position of three dimensional position of the fiducial marker.

[0221] Alternatively, the positions of the light beams on the screens (i.e., the intersection points) are determined by processing the images in the current image set. In some embodiments, image processing techniques are used to identify the location within the image of the intersection point. In some embodiments, a color of the light beam is analyzed to determine whether the light beam was emitted by the clutch or reference structure.

[0222] At operation 908, the relative positions and orientations of the clutch and the reference structure are determined based on the positions of the position indicators. As described previously, based on determining the three-dimensional positions of multiple of the fiducial markers secured to each of the clutch and the reference structure, the positions and orientations of the clutch and the reference structure can be determined. Alternatively, based on determining the intersection points of the light beams with the screens, the relative position and orientation of the clutch relative to the reference structure can be determined.

[0223] At operation 910, the relative positions of the patient's upper and lower dentition based on the determined positions of the clutch and reference structure. In some embodiments, the relative positions are determined based on information about the static relationship between the patient assembly and the patient's dentition.

[0224] At operation 912, it is determined whether there are more image sets to process through the loop. If so, the process 900 returns to operation 906 to process the next image set. If not, the process continues to operation 914.

[0225] At operation 914, the relative motion of the patient's upper and lower dentition is determined based on the determined relative positions in the image sets.

In some embodiments, a series of transformation matrixes are generated that correspond to the relative movement of the patient's lower dentition relative to the upper dentition in each of the image sets. This series of transformation matrixes can then be sequentially applied to a digital model of the patient's lower dentition to cause the lower dentition to digitally move in accordance with the captured motion. In this manner, the motion data is used as a digital articulator.

[0226] At operation 916, the approximate location and motion of the screw axis is inferred using the determined relative motion. In some embodiments, at least a portion of the image sets are captured while the patient's mandible is moving in a hinge motion (i.e., simply opening and closing without any excursive or protrusive movement). These image sets may be labeled, stored separately, or otherwise distinguished from the other image sets. The motion data for the image sets corresponding to this hinge movement can be analyzed to determine the approximate location of the screw axis. For example, the motion data can be fit to a circular arc. The location of the center of the circular arc can then be determined. In some embodiments, it is then determined that the screw axis passes through the center of the circle along a line that is orthogonal to the plane of the circular arc. Once the screw axis is inferred, the movement of the screw axis can be inferred as well. The relative motion data for the mandible relative to the maxilla can be applied to the screw axis to determine the movement of the screw axis.

[0227] FIG. 29 illustrates an example clutch 920 and an example transfer assembly 922. The clutch 920 is example of a clutch such as the clutch 462 shown in FIG. 15. The clutch 920 may include fiducial markers similar to the fiducial markers 466.

[0228] The transfer assembly 922 is usable to transfer coordinate information to a physical articulator. The coordinate information may be digitally derived based on the movement data and/or the inferred screw axis location. For example, the transfer assembly 922 may be usable to position the clutch 920 relative to a physical articulator in a position that allows the physical articulator to closely match the movement derived using the system 100.

[0229] The transfer assembly 922 includes a main body 924, sliding blocks

926a, 926b, and pivot arms 928a, 928b. The main body 924 is usable to adjust the width of the transfer assembly 922. The main body 924 may be a horizontally aligned linear body. The main body 924 includes a mounting assembly 930 and translation markings 932a, 932b. The mounting assembly 930 is usable to mount the clutch 920 to the transfer assembly 922. In some embodiments, the mounting assembly 930 comprises one or more apertures through which pins or keyed pins of the clutch 920 can removably fit to mount the clutch 920 to the transfer assembly 922. Typically, the mounting assembly is configured to mount the clutch 920 in a precise known relationship to the transfer assembly 922.

[0230] The translation markings 932a, 932b comprise a series of markings to indicate the width of the transfer assembly 922. In various embodiments, the translation markings 932a, 932b are disposed at different locations. For example, the translation markings 932a, 932b may each include a plurality of markings at 1 mm intervals. Other distances are possible too.

[0231] The sliding blocks 926a, 926b slide along the main body 924 to define the width of the transfer assembly 922. In some embodiments, the sliding blocks 926a, 926b include locking assemblies 934a, 934b and alignment indicators 936a, 936b. Although alternatives are possible, the sliding blocks 926a, 926b typically move independently of each other. In use, the sliding blocks 926a, 926b slide along the main body 924 to a specified position, which can be determined with reference to the translation markings 932a, 932b. In this manner, the sliding blocks 926a, 926b define the width of the transfer assembly 922. In some embodiments, the sliding blocks 926a, 926b include locking assemblies 934a, 934b to lock the sliding blocks 926a, 926b in a position relative to the translation markings 932a, 932b. In some embodiments, the locking assemblies 934a, 934b comprise one or more knobs or thumb screws.

[0232] The alignment indicators 936a, 936b are usable to indicate the rotational position of the pivot arms 928a, 928b. In some embodiments, the alignment indicators 936a, 936b each comprise a single line to mark a place by which the rotation of the pivot arms 928a, 928b can be compared.

[0233] The pivot arms 928a, 928b rotate to adjust the position of the transfer assembly 922. Although alternatives are possible, in this example, the pivot arms are rotatably connected to the sliding blocks 926a, 926b. In some embodiments, the pivot arms 926a, 926b include angle markings 938a, 938b, sliding blocks 940a,

940b, translation markings 942a, 942b, and locking assemblies 944a, 944b.

[0234] In this example, the angle markings 938a, 938b are disposed on a rounded end of the pivot arm. The angle markings 938a, 938b rotate with the pivot arm. The angle markings 938a, 938b can then be compared to the alignment indicators 936a, 936b to determine the rotation of the pivot arms 928a, 928b relative to the sliding blocks 926a, 926b (and therefore to the main body 924). Once the pivot arms 928a, 928b are rotated to a specified position, the locking assemblies 944a, 944b can be used to lock the rotation of the pivot arms 928a, 928b. The locking assemblies 944a, 944b may be similar to the locking assemblies 934a, 934b.

[0235] The sliding blocks 940a, 940b slide along the pivot arms 928a, 928b to adjust the depth of the transfer assembly 922. As mentioned above, the pivot arms 928a, 928b include translation markings 942a, 942b, which can be used as a reference in aligning the sliding blocks 940a, 940b at a specified distance from the main body 924. The translation markings 942a, 942b may be similar to the translation markings 932a, 932b.

[0236] In some embodiments, the sliding blocks 940a, 940b include articulator couplers 946a, 946b and locking assemblies 948a, 948b. The articulator couplers 946a, 946b are configured to mate with a feature of a target articulator. Depending on the target articulator, the articulator couplers 946a, 946b will have different forms.

[0237] The locking assemblies 948a, 948b are configured to lock the sliding blocks 940a, 940b at a specified position along the pivot arms 928a, 928b. The locking assemblies 948a, 948b may be similar to the locking assemblies 934a, 934b.

[0238] In some embodiments, the motion determining device 106 or another component of the system 100 determines parameters for the transfer assembly 920. Examples parameters include the positions of the sliding blocks 926a, 926b relative to the translation markings 932a, 932b; the rotation of the pivot arms 928a, 928b relative to the sliding blocks 926a, 926b, which can be evaluated with reference to the angle markings 938a, 938b and the alignment indicators 936a, 936b; and the positions of the sliding blocks 940a, 940b relative to the translation markings 942a, 942b. These parameter settings can be displayed on a display device of a computing device, printed on a report, or otherwise communicated to a user. The user can then adjust the transfer assembly 920 to match the specified settings. Once setup, the transfer assembly can be used to mount a stone model of the upper dentition to an articulator at the position associated with the specified settings. A stone model of the lower dentition can then be mounted relative to the stone model of the upper dentition (e.g., using a bite record). In this manner, the transfer assembly 922 can be used to mount stone models of the dentition on an articulator so as to best match the movement data captured using the system 100.

[0239] In some embodiments of the transfer assembly 920, some or all of the translation markings 932a, 932b, 942a, 942b and angular markings 938a, 938b are replaced with digital readouts that are based on linear and/or rotary encoders.

[0240] FIG. 30 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.

[0241] The computing device illustrated in FIG. 30 can be used to execute the operating system, application programs, and software modules described herein.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] 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, 802.1 la/b/g/n, cellular, ultra- wideband (UWB), ZigBee, or other radio frequency communication systems in some possible embodiments.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] 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.

[0253] 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. [0254] The computing device illustrated in FIG. 30 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.

[0255] In a non-limiting example, a clutch is attached to an emitter that projects three laser beams. Two of the laser beams are co-linear and project in opposite directions. The third laser beam is perpendicular to the first two laser beams. All three laser beams are co-planar. A clutch-emitter assembly is attached to each arch. The emitters project laser dots onto three translucent screens such that one upper arch and one lower arch laser dot appears on each screen. Each screen is viewed by a separate video camera. The cameras are synchronized such that they capture frames simultaneously or nearly simultaneously. Variations in the alignment of the screens to each other and the cameras is compensated for in software. Camera field-of-view distortion is also compensated for in software. The upper arch dot is distinguished from the lower arch dot on each screen using one or more of the following techniques: upper arch dots are assumed to be those highest on the screens and lower arch dots are assumed to be those lowest on the screens; upper arch dots are projected in one color and lower arch dots are projected in a different color; and dots are pulsed such that upper arch dots are projected and imaged after which lower arch dots are projected and imaged.

[0256] The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims.