Combining data from multiple dental structure scans

Abstract

To provide novel methods for combining data from multiple dental anatomy scans.SOLUTION: A method of combining dental anatomy data includes, by the use of a computing device: receiving volumetric dental data and superficial dental data; segmenting the crowns of the volumetric dental data from the roots of the volumetric dental data; segmenting the crowns of the superficial dental data from the gingiva of the superficial dental data; transforming superficial dental data of the crowns to substantially align with volumetric dental data of the crowns; stitching the transformed superficial dental data of the crowns to volumetric dental data of the crowns; and outputting, for display, image data based on the combined dental data.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to dental imaging, and more particularly to systems and techniques used to manipulate data obtained from dental imaging processes. [Background technology]

[0002] The field of orthodontics is concerned with repositioning a patient's teeth to improve their function and aesthetic appearance. Orthodontic treatment using braces or alignment trays benefits from imaging of the patient's dental structure, such as teeth, roots, or other parts of the dental structure. Imaging of the patient's dental structure can be performed using a variety of imaging systems and techniques. Data obtained from two or more different imaging devices can be combined to provide a more comprehensive picture of the patient's dental structure. Summary of the Invention

[0003] Combining dental structure data from two or more different imaging devices, e.g., combining superficial dental structures with subgingival dental structures derived from difference scan sources, may include transforming a portion of a first data set to align with a corresponding portion of a second data set to reduce distortion of dental structure features. For example, a computing device for combining dental structure data may be configured to receive first dental data representative of a patient's three-dimensional dental structure and second dental data representative of the patient's three-dimensional dental structure. The computing device may be configured to segment a first subset of the first dental data from the second subset of the first dental data. At least a portion of the second dental data may correspond to the first subset of the first dental data. For example, the second dental data and the first subset of the first dental data may represent the same portion of the patient's dental structure. The computing device may be configured to transform the corresponding portion of the second dental data to substantially align with the first dental data. The computing device may be configured to generate combined dental data by replacing a first subset of the first dental data with the transformed second dental data and splicing the transformed second dental data with the second subset of the second dental data. The computing device may be configured to output image data for display based on the combined dental data.

[0004] In some examples, a method includes receiving, by a computing device, volumetric dental data indicative of a patient's three-dimensional subgingival dental structure; receiving, by the computing device, superficial dental data indicative of the patient's three-dimensional superficial dental structure; segmenting, by the computing device, a first subset of the volumetric dental data representing crowns of the patient's teeth from a second subset of the volumetric dental data representing roots of the patient's teeth, the first subset of the volumetric dental data indicative of a first spatial orientation of the crowns and the second subset of the volumetric dental data indicative of a spatial orientation of the roots; and segmenting, by the computing device, the first subset of the superficial dental data representing the crowns from the second subset of the superficial dental data representing the patient's gingiva, the first subset of the superficial dental data indicative of a second spatial orientation of the crowns. and a second subset of the superficial dental data representing the root of the tooth. The method may include segmenting the first subset of the superficial dental data representing the root of the tooth, the first subset of the superficial dental data representing the second spatial orientation of the tooth, and the second subset of the superficial dental data representing the root of the tooth; transforming, by the computing device, the first subset of the superficial dental data representing the second spatial orientation of the tooth so that the second spatial orientation of the tooth is substantially aligned with the first spatial orientation of the tooth; replacing, by the computing device, the first subset of the subgingival data representing the first spatial orientation of the tooth with the transformed first subset of the superficial dental data representing the second spatial orientation of the tooth and splicing the transformed first subset of the superficial dental data representing the second spatial orientation of the tooth with the second subset of the volumetric dental data representing the root of the tooth to generate combined dental data; and outputting, by the computing device, image data based on the combined dental data for display.

[0005] In some examples, the method may include receiving, by a computing device, first dental data representing a first three-dimensional dental structure of the patient; receiving, by the computing device, second dental data representing a second three-dimensional dental structure of the patient; segmenting, by the computing device, a first subset of the first dental data from the second subset of the first dental data, wherein at least a portion of the second dental data corresponds to the first subset of the first dental data; transforming, by the computing device, the corresponding portion of the second dental data to substantially align with the first dental data; replacing, by the computing device, the first subset of the first dental data with the transformed corresponding portion of the second dental data and splicing the transformed second dental data into the second subset of the second dental data to generate combined dental data; and outputting, by the computing device, image data for display based on the combined dental data.

[0006] In some examples, a non-transitory computer-readable storage medium storing computer system executable instructions that, when executed, include receiving volumetric dental data indicative of a patient's three-dimensional subgingival dental structure; receiving superficial dental data indicative of the patient's three-dimensional superficial dental structure; segmenting a first subset of the volumetric dental data representative of the patient's tooth crowns from a second subset of the volumetric dental data representative of the patient's tooth roots, wherein the first subset of the volumetric dental data is indicative of a first spatial orientation of the tooth crowns and the second subset of the volumetric dental data is indicative of a spatial orientation of the tooth roots; and segmenting the first subset of the superficial dental data representative of the tooth crowns from the second subset of the superficial dental data representative of the patient's gingiva, wherein the first subset of the superficial dental data is indicative of a first spatial orientation of the tooth crowns and the second subset of the volumetric dental data is indicative of a spatial orientation of the tooth roots. a first subset of the subgingival data representing the first spatial orientation of the crown and a second subset of the superficial dental data representing the spatial orientation of the root; transforming the first subset of the superficial dental data representing the second spatial orientation of the crown such that the second spatial orientation of the crown substantially aligns with the first spatial orientation of the crown; replacing the first subset of the subgingival data representing the first spatial orientation of the crown with the transformed first subset of the superficial dental data representing the second spatial orientation of the crown and splicing the transformed first subset of the superficial dental data representing the second spatial orientation of the crown with the second subset of the volumetric dental data representing the root to generate combined dental data; and outputting image data for display based on the combined dental data.

[0007] The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will become apparent from the description and drawings, and from the claims. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a conceptual diagram illustrating an example system configured to combine data of a patient's dental structure.

[0009] [Figure 2] 1 is an exemplary digital image generated using volumetric dental data showing a patient's three-dimensional subgingival dental structure.

[0010] [Figure 3] 1 is an exemplary digital image generated using volumetric dental data showing a patient's three-dimensional subgingival dental structure.

[0011] [Figure 4] 1 is an exemplary digital image generated using superficial dental data showing a patient's three-dimensional superficial dental structure.

[0012] [Figure 5] FIG. 1 is a flow diagram of an exemplary technique for combining dental structure data from two or more different imaging devices.

[0013] [Figure 6] 1 is an exemplary digital image representing combined dental data including corresponding portions of transformed crowns of superficial dental data stitched to bone and roots of volumetric dental data.

[0014] [Figure 7] FIG. 1 is a flow diagram of an exemplary technique for combining dental structure data from two or more different imaging devices.

[0015] [Figure 8A] 1 is an exemplary digital image representing combined dental data including a corresponding portion of a transformed crown of the superficial dental data stitched to a root of the volumetric dental data. [Figure 8B] 1 is an exemplary digital image representing combined dental data including a corresponding portion of a transformed crown of the superficial dental data stitched to a root of the volumetric dental data.

[0016] [Figure 9A] FIG. 1 illustrates an exemplary technique for transforming dental structure data. [Figure 9B] FIG. 1 illustrates an exemplary technique for transforming dental structure data. [Figure 9C] FIG. 1 illustrates an exemplary technique for transforming dental structure data.

[0017] [Figure 10A] 1 is an exemplary image illustrating an optimal registration of a dental crown (eg, superficial dental data) to a dental root (eg, root of volumetric dental data). [Figure 10B] 1 is an exemplary image illustrating an optimal registration of a dental crown (eg, superficial dental data) to a dental root (eg, root of volumetric dental data).

[0018] [Figure 11A] FIG. 1 illustrates an exemplary technique for transforming dental structure data using centroids. [Figure 11B] FIG. 1 illustrates an exemplary technique for transforming dental structure data using centroids. [Figure 11C] FIG. 1 illustrates an exemplary technique for transforming dental structure data using centroids.

[0019] [Figure 12A] 1A-1C illustrate exemplary techniques for transforming dental structure data, including vertical and horizontal rotation. [Figure 12B] 1A-1C illustrate exemplary techniques for transforming dental structure data, including vertical and horizontal rotation. [Figure 12C] 1A-1C illustrate exemplary techniques for transforming dental structure data, including vertical and horizontal rotation. [Figure 12D] 1A-1C illustrate exemplary techniques for transforming dental structure data, including vertical and horizontal rotation.

[0020] [Figure 13]FIG. 1 is a flow diagram illustrating an exemplary technique for transforming dental structure data.

[0021] [Figure 14] FIG. 1 is a flow diagram illustrating an exemplary technique for transforming dental structure data.

[0022] [Figure 15] FIG. 1 is a flow diagram illustrating an exemplary technique for transforming dental structure data.

[0023] [Figure 16] FIG. 1 is a block diagram illustrating an exemplary computing environment.

[0024] [Figure 17] FIG. 1 is a flow diagram illustrating an exemplary technique for transforming dental structure data. DETAILED DESCRIPTION OF THE INVENTION

[0025] The systems and techniques described herein can be used to combine dental structure data (with respect to tooth position and orientation) from different types of scans with improved overall accuracy and alignment at image joints. Combining dental structure data from two or more different imaging devices, for example, combining a first data set including subgingival dental structure with a second data set including superficial dental structure derived from a differential scan source, may include transforming portions of the first data set to align with corresponding portions of the second data set to reduce distortion of dental structure features.

[0026] Dental imaging systems may capture superficial dental structures, subgingival dental structures, or both. Superficial dental structures include the patient's tooth structures above the gums, such as the tooth surface contours and spacing. Subgingival dental structures include the patient's tooth structures below the gums, such as the tooth roots, alveolar bone, and cortical bone. Some dental imaging systems may capture more accurate images of superficial or subgingival dental structures. For example, intraoral scanners such as the 3M True Definition Scanner can generate higher-resolution images of superficial dental structures compared to other dental imaging systems. In contrast, cone beam computed tomography (CBCT, 3D X-ray) scanners or magnetic resonance imaging (MRI) scanners can generate higher-resolution images of subgingival dental structures compared to other dental imaging systems. In some embodiments, CBCT, 3D X-ray, or MRI can produce images with higher overall accuracy across the scan volume due to rigid fixation of components within the scanner; for example, the patient is held in a fixed relationship relative to the scanner during scanning, which also improves overall accuracy. Additionally or alternatively, some dental imaging systems are capable of capturing both superficial and subgingival dental structures, but may produce higher-resolution images of either the superficial or subgingival dental structures. Additionally or alternatively, some dental imaging systems may more accurately represent the position of teeth in three-dimensional space (e.g., overall accuracy), but have relatively lower resolution compared to other dental imaging systems. For example, CBCT and MRI scanners may have higher overall accuracy compared to intraoral scanners, but may have poorer resolution of surface detail. In contrast, intraoral scanners may have higher resolution of surface detail compared to CBCT and MRI scanners, but may have lower overall accuracy due to cumulative errors when multiple patches of scan data are stitched together to form a dental arch.

[0027] Combining crown-related data from an intraoral scan with root-related data from a CBCT scan can provide a higher resolution image of both tooth portions. However, combining crown-related data from an intraoral scan with root-related data from a CBCT scan can result in imprecise alignment and / or misalignment between the root and crown for a given tooth in the resulting combined image. This imprecise alignment and / or misalignment can result from distortions in the intraoral scan and local alignment errors of features between the scan types due to the absence of detail in the CBCT scan. The imprecise alignment and / or misalignment can result in a visible discontinuity, e.g., a step, between the crown and root in the resulting image where the data sets are combined, e.g., "stitched" together.

[0028] In some examples, the systems and techniques described herein can improve integration between different data sets by rectifying an intraoral scan and registering it to a CBCT (or MRI) scan. Additionally or alternatively, the systems and techniques described herein can improve the usefulness of CBCT scans in orthodontic treatment planning by more accurately depicting the overall position of tooth crowns within the oral cavity, allowing clinicians to plan setting and tooth movements with greater confidence so that tooth roots do not interfere with one another and / or one or more of implants, mini-screws, or cortical bone.

[0029] FIG. 1 is a conceptual diagram illustrating an exemplary system 100 configured to combine data of a dental structure of a patient 101. The system 100 includes a computing device 102 configured to receive first dental data indicative of the three-dimensional dental structure of the patient 101 from a first imaging device 106 and second dental data indicative of the three-dimensional dental structure of the patient 101 from a second imaging device 108. The system 100 may include additional components not shown in FIG. 1 for clarity. For example, the system 100 may include a power supply that provides power to the components of the system 100. Similarly, the components of the system 100 shown in FIG. 1 may not be required in every embodiment of the system 100.

[0030] The computing device 102 may include, for example, a desktop computer, a laptop computer, a tablet computer, a workstation, a server, a mainframe, a cloud computing system, etc. The computing device 102 is configured to receive volumetric dental data from a first imaging device 106 and superficial dental data from a second imaging device 108. In some embodiments, the computing device 102 may be configured to control the first imaging device 106 and the second imaging device 108. For example, the computing device 102 may be configured to cause the first imaging device 106 and / or the second imaging device 108 to acquire volumetric dental data and / or superficial dental data, respectively. In the embodiment of FIG. 1 , the computing device 102 includes a processing circuit 110, a communications unit 112, a user interface 114, a memory 116, and an image processing module 118. In some embodiments, the computing device 102 may include additional components or fewer components than those shown in FIG. 1 .

[0031] Processing circuitry 110 is configured to implement functions and / or processing instructions for execution within computing device 102. Processing circuitry 110, as well as other processors, controllers, control circuits, etc. described herein, may include one or more processors. Processing circuitry 110 may include any combination of integrated circuits, discrete logic circuits, and analog circuits, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), or field programmable gate arrays (FPGAs). In some embodiments, processing circuitry 110 may include multiple components, such as any combination of one or more microprocessors, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuits and / or analog circuits.

[0032] The communications unit 112 may be configured to communicate with external devices (e.g., the first imaging device 106, the second imaging device 108, or a server) over one or more networks, such as one or more wired or wireless networks. The communications unit 112 may be a network interface card, such as an Ethernet card, an optical transceiver, a radio frequency transceiver, or any other type of device capable of sending and receiving information. Other examples of such network interfaces may include a Wi-Fi radio or a USB. In some embodiments, the computing device 102 utilizes the communications unit 112 to wirelessly communicate with external devices.

[0033] The user interface 114 includes input devices 120 and output devices 122. The input devices 120 may include one or more input devices configured to receive input from a user via tactile, audio, or video sources. Examples of the input devices 120 include, but are not limited to, a mouse, a keyboard, a voice response system, a video camera, a microphone, a touchscreen, or a device for detecting commands from a user. The output devices 122 may include one or more output devices configured to provide output to a user using audio or video media. Examples of the output devices 122 may include, but are not limited to, a display, a sound card, a video graphics adapter card, or a device for converting signals into an appropriate form that is understandable to a human or a machine.

[0034] The memory 116 may be configured to store information within the computing device 102 during operation. The memory 116 may include a computer-readable storage medium or a computer-readable storage device. In some embodiments, the memory 116 may store program instructions. The program instructions may include one or more program modules executable by the processing circuit 110. When executed by the processing circuit 110, such program instructions cause the processing circuit 110 to provide the functionality attributed to the processing circuitry herein. The program instructions may be embodied in software, firmware, and / or RAMware. The memory 120 may include any one or more of volatile, non-volatile, magnetic, optical, or electrical media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other digital medium.

[0035] Computing device 102 may be communicatively coupled to first imaging device 106 and second imaging device 108 using respective communication connections. In some embodiments, the communication connections may include a network link, such as an Ethernet or other network connection. Such connections may be wireless connections, wired connections, or a combination of both. In some embodiments, the communication connections may include other types of device connections, such as USB, IEEE 1394, etc. For example, computing device 102 may be communicatively coupled to first imaging device 106 and second imaging device 108 via wires or wirelessly.

[0036] The first imaging device 106 may be configured to acquire digital image data including volumetric dental data indicative of the patient's 101 three-dimensional subgingival dental structures. The first imaging device 106 may include a cone beam computed tomography (CBCT) scanner, a magnetic resonance imaging (MRI) scanner, or any other imaging device configured to generate digital image data capable of penetrating and distinguishing between different types of dental structure tissue. The subgingival dental structures include the patient's 101 dental structures above and below the gums. For example, the subgingival dental structures may include teeth, tooth roots, alveolar bone, and cortical bone. In some embodiments, the subgingival dental structures may include at least one of the patient's 101 maxilla, mandible, or a portion of the patient's 101 skull.

[0037] FIG. 2 illustrates an exemplary digital image 200 generated using volumetric dental data depicting three-dimensional subgingival dental structures of a patient 101. The digital image 200 represents volumetric dental data acquired from a CBCT scan of a lower portion of the patient's 101 skull 202, including an upper jaw 204 and a lower jaw 206, represented in a DICOM image file format. In some examples, the first imaging device 106 may be configured to generate volumetric dental data including a density-weighted point cloud. The density-weighted point cloud may be used to resolve hard tissues of the subgingival dental structures and soft tissues of the subgingival dental structures. For example, the hard tissues may include at least one of enamel, dentin, cementum, alveolar bone, or cortical bone. The soft tissues may include at least one of the hard palate, gums, tongue, oral mucosa, periodontal ligament, cartilage, muscle, or skin. In this manner, the first imaging device 106 may generate volumetric dental data including a first subset representing the first tissue and a second subset representing the second tissue.

[0038] In some examples, the computing device 102, e.g., the processing circuit 110, may be configured to filter the volumetric dental data using at least one density threshold based on at least one density of hard or soft tissue. In some embodiments, the first imaging device 106 may include a preprocessing circuit configured to filter the subgingival data. The at least one density threshold may include an upper and lower density of at least one tissue of the dental structure. For example, the at least one density threshold may include an upper and lower density of at least one of enamel, dentin, cementum, alveolar bone, cortical bone, hard palate, gingiva, tongue, oral mucosa, periodontal ligament, cartilage, muscle, or skin. In the example digital image 200, only hard tissues, such as enamel and cortical bone, are shown because soft tissues have been filtered. Other hard tissues, such as alveolar bone, dentin, and enamel, may be present but may not be visible due to obstruction by overlying dental structures.

[0039] In some embodiments, two or more hard tissues represented by density-weighted point clouds can be resolved on a single digital image. For example, FIG. 3 shows an exemplary digital image 300 generated using volumetric dental data depicting the three-dimensional subgingival dental structure of patient 101. Digital image 300 represents volumetric dental data obtained from a CBCT scan of the lower portion of patient 101's skull 302, including upper jaw 304 and lower jaw 306. Thus, the terms image and imaging, as used herein, are not limited to optical imaging but include imaging of dental structures hidden from view. Digital image 300 represents a first subset 308 of subgingival dental data depicting the three-dimensional subgingival dental structure of patient 101 and a second subset 310 of subgingival dental data depicting the three-dimensional subgingival dental structure of patient 101. As with digital image 200, soft tissue has been filtered so that only hard tissue is shown. The first subset 308 includes the crowns 312 of the teeth in the maxilla 304 and mandible 306. For example, the first subset 308 may include tissue containing enamel, dentin, and cementum. The second subset 310 includes the bone 314 of the maxilla 304 and mandible 306. For example, the second subset 310 may include tissue including cortical bone and alveolar bone. The area indicated by the dashed line may include a tooth root, such as root 316, where the first subset 308 and the second subset 310 overlap. Each of the first subset 308 and the second subset 310 may include a plurality of triangle vertices that define a mesh. In some embodiments, the mesh may be represented by other points, lines, and / or planes in three-dimensional space, such as a quadrilateral or hexagonal mesh, a Bezier surface, a Non-Uniform Rational Basis Spline (NURBS) surface, a parametric solid, or other surface representation. In some examples, where the periodontal ligament has been filtered out, small gaps may exist between the tooth root 316 and the alveolar bone 314. In some examples, the alveolus (e.g., the socket in the alveolar bone) of each tooth may be capped-off to form a continuous surface on the occlusal side of the alveolar process.Thus, using the first subset 308 and the second subset 310, the crown 312 may be segmented from the bone 314 and the root 316.

[0040] A second imaging device 108, such as that shown in FIG. 1 , may be configured to acquire digital image data including superficial dental data indicative of three-dimensional superficial dental structures of the patient 101. For example, the second imaging device 108 may include an intraoral scanner or imaging device configured to generate an optical impression of the dental structures. The superficial dental structures include the patient's dental structure above the gums and gingival structure, such as tooth surface contours, tooth spacing, and gingival surface contours. In some embodiments, the second imaging device 108 may be configured to scan the patient's 101's teeth, a physical impression of the patient's 101's teeth, or both. In embodiments in which the second imaging device 108 is configured to scan a physical impression of the patient's 101's teeth, the second imaging device 108 may include, for example, a CT scanner, a laser scanner, a structured light scanner, a 3D photogrammetry scanner, etc.

[0041] 4 shows an exemplary digital image 400 generated using superficial dental data showing three-dimensional superficial dental structure of patient 101. Digital image 400 represents superficial dental data obtained from an intraoral scan of tooth crowns 402 and gingiva 404 of patient 101. In some examples, second imaging device 108 may be configured to generate superficial dental data including triangular vertices that define a mesh representing an optically visible surface of at least a portion of the upper dental arch of patient 101 or the lower dental arch of patient 101. In some embodiments, the mesh may be represented by other points, lines, and / or planes in three-dimensional space, for example, by a quadrilateral or hexagonal mesh, a Bezier surface, a Non-Uniform Rational Basis Spline (NURBS) surface, a parametric solid, or other surface representation. Optically visible surfaces may include, for example, natural dental crowns (e.g., enamel), artificial dental crowns, bridges, implants, orthodontic appliances (e.g., brackets, buttons, hooks, bands, splints, etc.), or temporary fixation devices (mini screws).

[0042] The image processing module 118 includes an image data acquisition module 124, an image data adjustment module 126, a segmentation module 128, a transformation module 130, an image generation module 132, and an image output module 134. The image data acquisition module 124, the image data adjustment module 126, the segmentation module 128, the transformation module 130, the image generation module 132, and the image output module 134 may be implemented in various manners. For example, one or more of the image data acquisition module 124, the image adjustment module 126, the segmentation module 128, the transformation module 130, the image generation module 132, and the image output module 134 may be implemented as an application executed by the processing circuitry 110 or as part of a hardware unit of the computing device 102. The functions performed by one or more of the image data acquisition module 124, the image data adjustment module 126, the segmentation module 128, the transformation module 130, the image generation module 132, and the image output module 134 are described below with reference to the exemplary flow diagrams shown in FIGS. 5-14.

[0043] Figure 5 is a flow diagram of an exemplary technique for combining dental structure data from two or more different imaging devices. Although the technique of Figure 5 is described with respect to system 100 of Figure 1, in other embodiments, the technique of Figure 5 may be implemented using a different system. In addition, system 100 may implement other techniques for combining dental structure data from two or more different imaging devices.

[0044] 5 includes receiving, by the computing device 102, e.g., the image data acquisition module 124, first dental data representing a first three-dimensional dental structure of a patient (502). The technique also includes receiving, by the computing device 102, e.g., the image data acquisition module 124, second dental data representing a second three-dimensional dental structure of the patient (504). As described above, the first dental data may be acquired from the first imaging device 106, and the second dental data may be acquired from the second imaging device 108.

[0045] After receiving the first dental data, the technique shown in FIG. 5 includes segmenting, by the computing device 102, e.g., the segmentation module 128, a first subset of the first dental data from a second subset of the first dental data (506). For example, as described above with reference to FIG. 3, the first subset of volumetric dental data may represent the crown 312. The second subset of volumetric dental data may represent the root 316. In some examples, the first subset of volumetric dental data may indicate a first spatial orientation of the crown 312. In some examples, the second subset of volumetric dental data may indicate a spatial orientation of the root 316.

[0046] In some examples, at least a portion of the second dental data corresponds to the first subset of the first dental data. For example, as described above with reference to FIG. 4, the second dental data may include crown 402. Crown 402 may correspond to crown 312 of the first subset of the first dental data. By segmenting the first subset of the first dental data from the second subset of the first dental data, computing device 102 may define a subgingival portion and a superficial portion of the first dental data.

[0047] After segmenting the first dental data, the technique shown in FIG. 5 includes transforming, by the computing device 102, e.g., the transformation module 130, the corresponding portion of the second dental data to substantially align with the first subset of the first dental data. Transforming the second dental data may include using any suitable transformation. For example, a suitable transformation may be configured to transform the second dental data indicative of the spatial orientation of the dental crowns 402 to substantially align with the first subset of the first dental data indicative of the spatial orientation of the dental crowns 312. With respect to alignment of the entire dental arch, substantially aligning may include, for example, aligning dental features of the two respective scans to within about 2 millimeters to about 3 millimeters of each other, e.g., within about 0.25 millimeters. With respect to alignment of segments of the dental arch, substantially aligning may include aligning dental features of the two respective scans to within about 100 micrometers. With respect to aligning individual teeth or pairs of teeth, substantially aligning may include aligning dental features of two respective scans to within about 25 micrometers to about 50 micrometers. In some embodiments, substantial alignment may include alignment at or near the pixel or voxel resolution of the scanner, such that the substantial alignment may be based on a statistical average of many data points, such as a calculated centroid.

[0048] 5 includes generating, by the computing device 102, such as the image generation module 132, combined dental data by replacing a first subset of the first dental data with a transformed corresponding portion of the second dental data and stitching the transformed second dental data to a second subset of the first dental data. For example, generating the combined dental data may include replacing the crown 312 with a transformed corresponding portion of the crown 402 and stitching the transformed crown 402 to the bone 314 and / or the root 316.

[0049] After generating the combined dental data, the technique shown in FIG. 5 includes outputting (512) by the computing device 102, e.g., the image output module 134, image data based on the combined dental data for display, e.g., for the user interface 114. For example, FIG. 6 shows an exemplary digital image 600 representing the combined dental data, including a corresponding portion of the transformed crown 402 of the superficial dental data stitched to the bone 314 and root 316 of the volumetric dental data. In some embodiments, the outputting may include outputting the combined dental data to a clinic or manufacturing facility for fabrication of dental appliances, such as clear tray aligners, prostheses, etc.

[0050] Aspects of the technique of Figure 5 can be used with removable restorative dental appliances to design the removable dental appliance around a portion of the removable restorative dental appliance. In at least one embodiment, the first three-dimensional dental structure includes the removable restorative dental appliance worn by the patient, and in the second three-dimensional dental structure, the removable restorative dental appliance is not worn by the patient, or vice versa. In at least one embodiment, a first subset of the first dental data includes volumetric dental data of the removable restorative dental appliance, and a second subset of the first dental data includes volumetric dental data of the patient's dentition.

[0051] FIG. 17 shows a flow diagram of a method 1700 for using combined dental data from a removable restorative dental appliance. Method 1700 may be associated with the flow diagram of FIG. 5. For example, block 1702 may follow block 510. In at least one embodiment, method 1700 may relate to designing a removable dental appliance around a pontic of a removable restorative dental appliance such that the pontic is not used as an anchor for the removable dental appliance. Aspects of method 1700 may be implemented at a manufacturing facility for building sets of removable dental appliances.

[0052] At block 1702, the computing device 102 may receive the combined dental digital representation (e.g., as obtained by block 510). The combined dental data may be accessed by the computing device 102 in any manner, such as by being transmitted from another computing device or by accessing a local cache within the computing device 102. For example, the computing device 102 at a manufacturing facility receives digital dental structure data and prescription data from a clinic, including the initial positions of one or more teeth of the patient. Alternatively, the computing device 102 may retrieve the information from a database within the computing device 102 or otherwise accessible by the computer 102. If the clinic 14 has not already done so, a trained user associated with the computing device 102 may interact with a computerized modeling environment running on the computing device 102 to develop a treatment plan for the digital representation of the patient's tooth structure and generate prescription data 18. In other examples, the computing device 102 may automatically develop a treatment plan based solely on the patient's tooth structure and predefined design constraints.

[0053] At block 1704, the computing device 102 may determine the size and shape of the removable dental appliance for the patient based on the treatment plan. In at least one embodiment, the treatment plan excludes the segmented region (including at least a portion of the removable restorative dental appliance) from the tooth position adjustment of the adjacent teeth. For example, the computing device 102 may design the removable dental appliance such that the pontic from the removable restorative dental appliance is not subjected to forces while repositioning the adjacent teeth with the pontic.

[0054] The removable dental appliance can include an appliance body configured to at least partially surround a plurality of teeth in a patient's dental arch. In at least one embodiment, the appliance body includes a unitary material defining a shell shaped to receive at least one tooth of the patient. In at least one embodiment, the size and shape of the removable dental appliance include the location, size, and shape of the shell.

[0055] Once the computing device 102 receives the patient's tooth structure, the computing device 102 determines the size and shape of removable dental appliances for the patient at block 1704. The size and shape of the removable dental appliances are configured to reposition one or more of the patient's teeth from their initial positions to final positions when the removable dental appliances are worn by the patient. In the same or further embodiments, the computing device 102 determines the size and shape of a set of removable dental appliances 22 for the patient configured to be worn sequentially.

[0056] In some examples, determining the size and shape of the removable dental appliance includes selecting, by the computing device 102, the size and shape of the removable dental appliance according to a set of pre-defined design constraints. The set of pre-defined design constraints may include one or more factors including, but not limited to, at least one of minimum and maximum local forces applied to one or more of the surrounded teeth, at least one of minimum and maximum rotational forces applied to one or more of the surrounded teeth, at least one of minimum and maximum translational forces applied to one or more of the surrounded teeth, at least one of minimum and maximum resultant forces applied to one or more of the surrounded teeth, and at least one of minimum and maximum stress or strain applied to the removable dental appliance when the removable dental appliance is worn by a patient and the surrounded teeth are in their initial positions.

[0057] When determining the size and shape of the removable dental appliances, the computing device 102 may use finite element analysis (FEA) techniques to analyze the forces acting on the patient's teeth and the removable dental appliances. For example, the computing device 102 may apply FEA to a solid model of the patient's teeth, representing treatment including a set of ordered removable dental appliances, as the modeled teeth move from their initial positions to their final positions. The computing device 102 may use FEA to select appropriate removable dental appliances to apply desired forces to the teeth. In addition, the computing device 102 may use a virtual articulator to determine contact points between the teeth throughout the movement of the modeled teeth during treatment. The computing device 102 may further include occlusal contact forces, such as intercuspation forces, in the FEA force analysis when designing the dental appliances in the set of ordered removable dental appliances. The computing device 102 may further determine the order in which the teeth are to be moved to optimize force application, reduce treatment time, improve patient comfort, etc. The computing device 102 may further determine overcorrection of the dentition to account for relapse after treatment is completed.

[0058] In some examples, determining the size and shape of the removable dental appliance includes selecting, by the computing device 102, a thickness of the appliance body or shell, positioning member bending region, to provide suitable rigidity for repositioning one or more patient's teeth from their initial position to their final position when the removable dental appliance is worn by the patient. In some examples, the selected thickness may be in a range from about 0.10 millimeters to about 2.0 millimeters, such as from about 0.2 millimeters to about 1.0 millimeters, or from about 0.3 millimeters to about 0.75 millimeters. In some examples, the computing device 102 may further select a material for the removable dental appliance according to predetermined design constraints.

[0059] The dimensions and shape of the removable dental appliance for the patient may be presented to the user via an image output module of the computing device 102, as in block 512. In embodiments in which the dimensions and shape of the removable dental appliance are presented to the user, the user may have an opportunity to adjust design constraints or directly adjust the dimensions and shape of the removable dental appliance before the design data is sent to the computer-aided manufacturing system 20. In some embodiments, the dimensions and shape of the removable dental appliance may be presented to the user directly by the computing device 102 as the removable dental appliance is manufactured by the computer-aided manufacturing system 20. For example, the computing device 102 can send a digital model of the removable dental appliance to the computer-aided manufacturing system 20, and the computer-aided manufacturing system 20 manufactures the removable dental appliance according to the digital model from the computing device 102.

[0060] However, even in embodiments where the dimensions and shape of the removable dental appliance for the patient can be presented to the user via the user interface of the computing device 102, after user approval, the computing device 102 sends a digital model of the removable dental appliance to the computer-aided manufacturing system 20 in block 1706, and the computer-aided manufacturing system 20 manufactures the removable dental appliance according to the digital model from the computing device 102.

[0061] In some examples, the computer-aided manufacturing system 20 may include a 3D printer. Forming the appliance body may include printing at least one of the spring members, attachments, shells, positioning members, bend regions, stress-reduced regions, and biasing portions with the 3D printer. In other examples, forming the appliance body may include printing a representation of the patient's teeth with the 3D printer, thermoforming the appliance body over the tooth representation, and trimming excess material to form at least one of the spring members, attachments, shells, positioning members, bend regions, stress-reduced regions, and biasing portions. The representation of the patient's teeth may include raised surfaces that facilitate thermoforming to form at least one of the spring members, attachments, shells, positioning members, bend regions, stress-reduced regions, and biasing portions in the trimmed appliance body.

[0062] The techniques of method 1700 may be applied to the design and manufacture of each of the ordered sets of removable dental appliances 22. For example, each removable dental appliance in the ordered set of removable dental appliances 22 may be configured to incrementally reposition a patient's teeth. In this manner, the ordered set of removable dental appliances 22 may be configured to reposition a patient's teeth to a greater extent than any one of the removable dental appliances in the set of removable dental appliances 22. Such an ordered set of removable dental appliances 22 may be specifically configured to incrementally reposition one or more of the patient's teeth from their initial positions to their final positions as the removable dental appliances in the patient's ordered set of removable dental appliances 22 are sequentially worn by the patient.

[0063] Figure 7 is a flow diagram of an exemplary technique for combining dental structure data from two or more different imaging devices. Although the technique of Figure 7 is described with respect to system 100 of Figure 1, in other embodiments, the technique of Figure 7 may be implemented using a different system. In addition, system 100 may implement other techniques for combining dental structure data from two or more different imaging devices.

[0064] The technique shown in FIG. 7 includes receiving, by a computing device 102, e.g., by an image data acquisition module 124, volumetric dental data indicative of a three-dimensional subgingival dental structure of a patient 101 (702). For example, the volumetric dental data may include data representing a digital image 300, as shown in FIG. 3. The technique also includes receiving, by a computing device 102, e.g., by an image data acquisition module 124, superficial dental data indicative of a three-dimensional superficial dental structure of the patient 101 (704). For example, as shown in Table 4, the superficial dental data may include dental data representing a digital image 400. Although not shown in FIG. 7, the technique may include controlling a first imaging device 106 to acquire the volumetric dental data, controlling a second imaging device 108 to acquire the superficial dental data, and communicating with a network to acquire the volumetric dental data, the superficial dental data, or a combination thereof.

[0065] After receiving the volumetric dental data, the technique shown in FIG. 7 includes segmenting, by the computing device 102, e.g., the segmentation module 128, a first subset of the volumetric dental data representing the patient's tooth crown from a second subset of the volumetric dental data representing the tooth root (706). For example, as described above with reference to FIG. 3, the first subset of the volumetric dental data may represent the tooth crown 312. The second subset of the volumetric dental data may represent the tooth root 316. In some examples, the first subset of the volumetric dental data may indicate a first spatial orientation of the tooth crown 312. In some examples, the second subset of the volumetric dental data may indicate a spatial orientation of the tooth root 316. By segmenting the first subset of the volumetric dental data from the second subset of the volumetric dental data, the computing device 102 may define a subgingival portion (e.g., tooth root 316) and a superficial portion (e.g., tooth crown 312) of the volumetric dental data.

[0066] In some examples, segmenting the first subset of volumetric dental data from the second subset of volumetric dental data may include segmenting, by the computing device 102, e.g., the segmentation module 128, a first spatial orientation of the crown 312 from a spatial orientation of the root 316 by combining points of the point cloud indicative of at least one of enamel, dentin, cementum, or a restorative material, and determining, by the computing device 102, e.g., the segmentation module 128, a triangular vertex mesh defining an exterior of the combined points. Determining the triangular vertex mesh may include wrapping the combined points of the point cloud in the triangular vertex mesh.

[0067] After receiving the superficial dental data, the technique shown in FIG. 7 includes segmenting (708), by the computing device 102, e.g., by the segmentation module 128, a first subset of the superficial dental data representing the crown from a second subset of the superficial dental data representing the patient's gingiva. For example, as described above with reference to FIG. 4, the first subset of the superficial dental data may represent the crown 402. The second subset of the superficial dental data may represent the gingiva 404. In some embodiments, the first subset of the superficial dental data may indicate a second spatial orientation of the crown 402. In some embodiments, the second subset of the superficial dental data may indicate a spatial orientation of the gingiva 404. By segmenting the first subset of the superficial dental data from the second subset of the superficial dental data, the computing device 102 may define a portion of the superficial dental data that corresponds to a superficial portion of the volumetric dental data. For example, the crown 402 as described above with reference to FIG. 4 may correspond to the crown 312 as described above with reference to FIG. 4.

[0068] Although not shown in FIG. 7 , in some embodiments, the technique may include defining, by the computing device 102, a first group including a first subset of the volumetric dental data and a portion of the second subset of the volumetric dental data. The technique may also include defining, by the computing device 102, a second group including a portion of the first subset of the superficial dental data. The portion of the first subset of the superficial dental data may correspond to the portion of the first subset of the volumetric dental data. For example, the first group may include the crowns of the upper or lower dental arch of the volumetric dental data and the corresponding roots of the upper or lower dental arch of the volumetric dental data, and the second group may include the crowns of the upper or lower dental arch of the superficial dental data. In this sense, the first and second groups may be considered to be respective dental arch shape objects.

[0069] In some examples, the first group may include a plurality of first groups, and the second group may include a plurality of second groups. Each first group of the plurality of first groups may include at least two crowns of the first subset of volumetric dental data and at least two corresponding roots of the second subset of volumetric dental data. Each second group of the plurality of second groups may include at least two crowns of the first subset of superficial dental data. Defining the first and second groups may reduce the computational intensity or time required to transform the superficial dental data.

[0070] 7 includes transforming (710), by the computing device 102, e.g., the transformation module 130, the first subset of superficial dental data indicating the second spatial orientation of the crowns, such that the second spatial orientation of the crowns substantially aligns with the first spatial orientation of the crowns. Transforming the first subset of superficial dental data may include using any suitable transformation. For example, transforming (710) may include transforming, by the computing device 102, e.g., the transformation module 130, the first subset of superficial dental data indicating the second spatial orientation of the crowns 402, such that the second spatial orientation of the crowns 402 substantially aligns with the first spatial orientation of the crowns 312. In some examples, transforming (710) may include applying multiple linear transforms to data representing different segments (or portions) of the dental arch, applying a continuous transformation function that varies along a path representing the dental arch to the data representing the dental arch, or both. In some embodiments, different segments of the dental arch may be as small as individual vertices of a triangular mesh representing the dental arch.

[0071] 7 includes, by the computing device 102, e.g., image generation module 132, generating combined dental data by replacing a first subset of subgingival data indicative of a first spatial orientation of the crown with a transformed first subset of superficial dental data indicative of a second spatial orientation of the crown, and stitching the transformed first subset of superficial dental data indicative of the second spatial orientation of the crown to a second subset of volumetric dental data representing the root (712). For example, generating the combined dental data may include replacing crown 312 with a transformed corresponding portion of crown 402, and stitching transformed crown 402 to bone 314 and / or root 316.

[0072] After generating the combined dental data, the technique shown in FIG. 7 includes outputting image data based on the combined dental data by the computing device 102, e.g., the image output module 134, for display, e.g., for the user interface 114 (714). For example, FIGS. 8A and 8B show exemplary digital images representing the combined dental data, including corresponding portions of transformed crowns from the superficial dental data stitched to roots from the volumetric dental data. FIG. 8A shows a dental image 750 representing a mandibular dental arch 752, including crowns 754 and roots 756 that meet at a smooth, continuous interface 758. The interface 758 does not include any significant step from the crowns 754 to the roots 756. FIG. 8B shows a dental image 770 representing a maxillary dental arch 772, including crowns 774 and roots 776 that meet at a smooth, continuous interface 778. The interface 778 does not include any significant step (visible discontinuity) from the crown 774 to the root 776 .

[0073] As discussed in more detail below, in some embodiments, converting (710) may include one or more of the techniques illustrated with reference to Figures 9A-15. Figures 9A-9C illustrate exemplary techniques for converting dental structure data. Although the techniques of Figures 9A-9C are described with respect to system 100 of Figure 1, in other embodiments, the techniques of Figures 9A-9C may be implemented using different systems. In addition, system 100 may implement other techniques for converting dental structure data.

[0074] The technique illustrated in the flow diagram of FIG. 9A may include translating, by the computing device 102, e.g., the transformation module 130, a second spatial orientation of the crown in the superficial dental data to substantially align with the first spatial orientation of the crown in the volumetric dental data (802). For example, as shown in FIG. 9B, the superficial dental data representing the spatial orientation of the crown 806 may be translated (e.g., translation 810) to substantially align with the volumetric dental data representing the spatial orientation of the crown 808. Although shown as a two-dimensional translation, the translation may be three-dimensional. The translation may include both positional and orientational translation components. In some embodiments, the translation may include a scaling component. The technique illustrated in FIG. 9A may include rotating, by the computing device 102, e.g., the transformation module 130, the second spatial orientation of the crown in the superficial dental data to substantially align with the first spatial orientation of the crown in the volumetric dental data (804). For example, as shown in Figure 9C, the superficial dental data representing the spatial orientation of the crown 806 may be rotated (e.g., rotated 812) to substantially align with the volumetric dental data representing the spatial orientation of the crown 808. Although shown as a single rotation along a single axis, the rotation may be about more than one axis.

[0075] In some embodiments, translating (802) and / or rotating (804) as a single monolithic object may define an "optimal alignment" of the second spatial orientation of the crown of the superficial dental data to the first spatial orientation of the crown of the volumetric dental data. In some embodiments, optimal alignment of the second spatial orientation of the crown of the superficial dental data (e.g., as a single monolithic object) to the first spatial orientation of the crown of the volumetric dental data (e.g., as a single monolithic object) may result in slight deviations due to distortions in the first spatial orientation of the crown of the volumetric dental data.

[0076] 10A and 10B are example images 900A and 900B illustrating optimal alignment of a crown 902 (e.g., the crown of crown 402) relative to a root 904 (e.g., the root of root 316). FIG. 10B illustrates a 90-degree rotation of the view shown in FIG. 10A. As shown in FIGS. 10A and 10B, optimal alignment may result in a step 906 in position between the crown 902 and the corresponding root 904. The step 906 may represent a misalignment in translation and / or rotation (e.g., a position error and an orientation error, respectively). In the example shown in FIGS. 10A and 10B, the magnitude of the position error is greater than the magnitude of the orientation error.

[0077] To reduce errors from optimal registration, centroids or other data features can be used to improve translational and / or rotational alignment. Figures 11A-11C illustrate an exemplary technique for transforming dental structure data using centroids. While the technique of Figure 11 is described with respect to system 100 of Figure 1, in other embodiments, the technique of Figure 11 may be implemented using a different system. Additionally, system 100 may implement other techniques for transforming dental structure data.

[0078] 11A includes determining, by the computing device 102, e.g., the transformation module 130, at least one of a dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structure landmarks, one or more mesh vertices, and one or more mesh triangles based on a first spatial orientation of the dental crowns of the volumetric dental data (1002). The technique shown in FIG. 11A includes determining, by the computing device 102, e.g., the transformation module 130, at least one of a dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structure landmarks, one or more mesh vertices, and one or more mesh triangles based on a second spatial orientation of the dental crowns of the superficial dental data (1004). As used herein, a centroid may include the geometric center of a triangle vertex mesh representing a respective dental structure feature or a surface of a feature of the dental structure data. The dental structure features may include entire dental arches, segments of dental arches, individual crowns, other landmarks (e.g., implants, prostheses, or features of natural dental structure), etc. The dental structure data features may include one or more sets of coordinates that represent one or more points on a mesh that defines the three-dimensional shape of the dental structure features.

[0079] The technique shown in FIG. 11A includes at least one of: by the computing device 102, e.g., the transformation module 130, modifying the position of or translating by rotating at least one of the arch centroid, one or more arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structure landmarks, one or more mesh vertices, and one or more mesh triangles of the second spatial orientation of the crown of the superficial dental data in three-dimensional space to substantially align them with at least one of the arch centroid, one or more arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structure landmarks, one or more mesh vertices, and one or more mesh triangles of the first spatial orientation of the crown of the volumetric dental data (1006).

[0080] For example, as shown in FIG. 11B , the computing device 102, e.g., the transformation module 130, may be configured to determine a centroid 1010 of the superficial dental data, which represents the spatial orientation of the crown 1012. Similarly, the computing device 102, e.g., the transformation module 130, may be configured to determine a centroid 1014 of the volumetric dental data, which represents the spatial orientation of the crown 1016. The computing device 102, e.g., the transformation module 130, may be configured to determine a translation 1018 from the centroid 1010 to the centroid 1014 and then apply the determined translation to each triangle vertex of the mesh defining the crown 1012. While shown as a two-dimensional translation, it will be understood that the translation may be three-dimensional. As shown in FIG. 11C , the computing device 102, e.g., the transformation module 130, may be configured to determine a rotation 1020 of the crown 1012, e.g., about the centroid 1010 as the axis of rotation, to substantially align it with the crown 1016.

[0081] Although shown in FIG. 11C as a single rotation along a single axis, the rotation may be about two or more axes. FIGS. 12A-12D illustrate exemplary techniques for transforming dental structure data, including vertical and horizontal rotations. While the techniques of FIGS. 12A-12D are described with respect to system 100 of FIG. 1, in other embodiments, the techniques of FIGS. 12A-12D may be implemented using different systems. Additionally, system 100 may implement other techniques for transforming dental structure data.

[0082] The technique shown in FIG. 12A includes determining (1102), by the computing device 102, e.g., the transformation module 130, one or more crown centroids of a first spatial orientation of the crown in the volumetric dental data and a second spatial orientation of the crown in the superficial dental data. The one or more centroids may include the geometric center of a triangular vertex mesh representing the surface of the crown in the respective dental data. For example, as shown in FIG. 11B, centroid 1120 may include the arithmetic mean position of all vertices of the mesh representing crown 1122, and centroid 1124 may include the arithmetic mean position of all vertices of the mesh representing crown 1126. In this manner, a respective centroid may be defined for each tooth in the dental arch of the patient 101 represented by the respective volumetric or superficial dental data.

[0083] The technique shown in FIG. 12A includes determining, by the computing device 102, e.g., the transformation module 130, a translation between one or more crown centroids of a first spatial orientation of the crowns in the volumetric dental data and one or more corresponding crown centroids of a second spatial orientation of the crowns in the epidermal dental data (1104). The technique shown in FIG. 12A also includes translating, by the computing device 102, e.g., the transformation module 130, each triangle vertex of a mesh defining the second spatial orientation of the crowns in the epidermal dental data by the translation (1106). For example, as shown in FIG. 11B, the computing device 102, e.g., the transformation module 130, may be configured to determine a translation 1128 from the centroid 1120 to the centroid 1124 and then apply the determined translation to each triangle vertex of the mesh defining the crown 1122. Although shown as a two-dimensional translation, the translation may be three-dimensional. In this manner, each tooth in the dental arch may be translated to intermediately align with a corresponding tooth at a first spatial orientation of the crown of the volumetric dental data.

[0084] 12A includes determining, by the computing device 102, e.g., the transformation module 130, a horizontal rotation angle α between a first vector between a first crown and a second crown of a first spatial orientation of the crowns of the volumetric dental data and a second vector between a third crown and a fourth crown of a second spatial orientation of the crowns of the superficial dental data, where the first crown corresponds to the third crown and the second crown corresponds to the fourth crown (1108). The technique also includes rotating, by the computing device 102, e.g., the transformation module 130, each triangle vertex of a mesh defining the third crown by the horizontal rotation angle α using the center of gravity of the third crown as a center of rotation (1110). 12C, the computing device 102, e.g., the transformation module 130, may be configured to determine a horizontal rotation angle α of the crown 1122 and rotate the crown 1122 about the centroid 1120 as the axis of rotation to substantially align with the crown 1126. In some examples, the first and second crowns include mesial-distal adjacent teeth, or in the case of the most mesial crown, crowns in adjacent quadrants of the dental arch. The horizontal rotation determination may be repeated for each tooth in the dental arch.

[0085] 12 includes determining, by the computing device 102, e.g., the transformation module 130, a vertical rotation angle θ between a third vector between a first crown and the centroid of a first spatial orientation of the crown in the volumetric dental data and a fourth vector between a third crown and the centroid of a second spatial orientation of the crown in the superficial dental data (1112). The technique also includes rotating, by the computing device 102, e.g., the transformation module 130, each triangle vertex of a mesh defining the third crown by the vertical rotation angle θ using the centroid of the third crown as a center of rotation (1114). For example, as shown in FIG. 12D , the computing device 102, e.g., the transformation module 130, may be configured to determine a longitudinal, vertical rotation angle θ of the crown 1122 and rotate the crown 1122 about the centroid 1120 as the rotation axis to substantially align it with the crown 1126.

[0086] In some embodiments, transforming the second spatial orientation of the crowns of the superficial dental data may include repeating horizontal and vertical rotations for each crown of the second spatial orientation of the crowns of the superficial dental data.

[0087] Figure 13 is a flow diagram of an exemplary technique for converting dental structure data. Although the technique of Figure 13 is described with respect to system 100 of Figure 1, in other embodiments, the technique of Figure 13 may be implemented using a different system. In addition, system 100 may implement other techniques for converting dental structure data.

[0088] 13 includes determining (1202) by the computing device 102, e.g., the transformation module 130, a first centroid of each first group of the plurality of first groups and a second centroid of each second group of the plurality of second groups. For example, as described above, the volumetric dental data and the superficial dental data may be subdivided into groups representing sections of the dental arch. Each centroid includes the geometric center of a triangular vertex mesh representing the surface of the respective group. Determining the group centroids may reduce computational intensity or time compared to determining the centroid of each dental crown.

[0089] 13 includes determining, by the computing device 102, e.g., the transformation module 130, a translation between each first centroid and a corresponding second centroid (1204). The technique shown in Figure 13 includes translating, by the computing device 102, e.g., the transformation module 130, each triangle vertex of each mesh defining each second group of the plurality of second groups by the translation (1206). In this manner, each group (e.g., each section of teeth in a dental arch) may be translated to be intermediately aligned with a corresponding group.

[0090] 13 includes determining, by the computing device 102, e.g., the transformation module 130, a vertical rotation angle θ between a first vector between each first centroid and a centroid of the plurality of first groups and a second vector between each second centroid and a centroid of the plurality of second groups (1208). The technique shown in FIG. 13 includes rotating, by the computing device 102, e.g., the transformation module 130, each triangle vertex of each mesh defining each second group of the plurality of second groups by the vertical rotation angle θ using the respective second centroid as a rotation center (1210). In some examples, transforming the second spatial orientation of the dental crowns of the superficial dental data may include repeating the vertical rotation for each second group of the plurality of second groups.

[0091] Figure 14 is a flow diagram of an exemplary technique for converting dental structure data. Although the technique of Figure 14 is described with respect to system 100 of Figure 1, in other embodiments, the technique of Figure 14 may be implemented using a different system. In addition, system 100 may implement other techniques for converting dental structure data.

[0092] 14 includes determining 1302, by computing device 102, e.g., transformation module 130, a first centroid for each first group of the plurality of first groups and a second centroid for each second group of the plurality of second groups. Step 1302 may be the same as or substantially similar to step 1202 described above.

[0093] The technique shown in FIG. 14 includes determining 1304, by the computing device 102, e.g., the transformation module 130, a degree of collinearity for each of the first and second centroids. For example, each first centroid may be connected to an adjacent first centroid by a first vector, and each second centroid may be connected to an adjacent second centroid by a second vector. The corresponding first and second vectors may be compared to determine the degree of collinearity. In some examples, linear regression may be used to fit a line to the multiple centroids. The line may be considered as an average line or trend of the multiple centroids. In some embodiments, the degree of collinearity may be based on a standard deviation of the multiple centroids from the line. For example, a larger deviation of a centroid from the line indicates less collinearity. In some embodiments, the degree of collinearity may be based on a root-mean-square (RMS) error calculation from the average line of the multiple centroids.

[0094] The technique shown in FIG. 14 includes determining, by the computing device 102, e.g., the transformation module 130, whether each respective degree of collinearity is greater than a threshold (1306). In some embodiments, the threshold may include the amount of translation and / or rotation required for perfect collinearity. For example, the threshold may include a translation of less than about 1 millimeter and a rotation of less than about 10 degrees, e.g., less than about 5 degrees. In examples where a line is fit to the center of gravity of the entire dental arch, the threshold may include a translation of less than about 20 millimeters, e.g., less than about 10 millimeters or less than about 1 millimeter. In examples where a line is fit to a segment of the dental arch, the threshold may include a translation of less than about 10 millimeters, e.g., less than about 5 millimeters or less than about 1 millimeter. In examples where a line is fit to a segment of the dental arch including only two teeth, the threshold may include a translation of substantially zero millimeters, e.g., zero or approximately zero within the scanner's error limits. In this manner, collinearity may be used to reduce computational intensity or time by transforming only the portion of the data that requires the threshold amount of transformation.

[0095] 14 includes dividing 1308, by the computing device 102, e.g., by the conversion module 130, each respective second group of the plurality of second groups into at least two subgroups. Each respective second group may be defined as a parent group. The at least two subgroups may be defined as child groups.

[0096] 14 includes adjusting 1310, by computing device 102, e.g., transformation module 130, an orientation of each respective second group of the plurality of second groups. In some embodiments, adjusting the orientation may be based on a function of the original orientation of each respective second group and the orientation of the parent group. For example, adjusting the orientation may include translating and / or rotating each respective second group based on a weighted average of vectors representing the transformations of the parent group and the child group.

[0097] The technique shown in FIG. 14 involves iteratively determining the centroid, determining the degree of collinearity, adjusting the orientation, and dividing each respective subgroup until each subgroup contains two tooth crowns (1312).

[0098] Figure 15 is a flow diagram of an exemplary technique for converting dental structure data. Although the technique of Figure 15 is described with respect to system 100 of Figure 1, in other embodiments, the technique of Figure 15 may be implemented using a different system. In addition, system 100 may implement other techniques for converting dental structure data.

[0099] The technique shown in Figure 15 includes determining 1402, by the computing device 102, e.g., the transformation module 130, dental arch centroids of the volumetric dental data and the superficial dental data. The technique shown in Figure 15 includes determining 1404, by the computing device 102, e.g., the transformation module 130, for each crown in a first spatial orientation of the crowns in the volumetric dental data and for each crown in a second spatial orientation of the crowns in the superficial dental data.

[0100] The technique shown in FIG. 15 includes translating (1406) by the computing device 102, e.g., the transformation module 130, each triangle vertex of a mesh that defines a second spatial orientation of the crown of the superficial dental data by a translational movement between the crown centroid of the first spatial orientation of the crown of the volumetric dental data and the corresponding crown centroid of the second spatial orientation of the crown of the superficial dental data.

[0101] The technique shown in FIG. 15 includes determining, by the computing device 102, e.g., the transformation module 130, a first spline function passing through the crown centroid of a first spatial orientation of the crown of the volumetric dental data and a second spline function passing through the crown centroid of a translated second spatial orientation of the crown of the superficial dental data (1408). The first spline function and the second spline function may include any suitable piecewise polynomial parameter curves. For example, the first spline function and the second spline function may include a cubic spline function or a hexagonal spline function (e.g., combining both translational and rotational components). In some embodiments, the first spline function and the second spline function may include other interpolating functions.

[0102] 15 includes determining 1410, by the computing device 102, e.g., by the transformation module 130, a three-dimensional affine transformation from the second spline function to the first spline function. The three-dimensional affine transformation may include any suitable number of parameters. For example, a 12-parameter affine transformation may be suitable for defining the relationship between data representing the three-dimensional image, e.g., volumetric dental data and superficial dental data. The three-dimensional affine transformation may include, but is not limited to, at least one of a translation component, a rotation component, or a scaling component.

[0103] In some embodiments, determining the three-dimensional affine transformation may include, by the computing device 102, e.g., the transformation module 130, determining, for each of the first spline functions at each of the crown centroids of the first spatial orientation of the crowns in the volumetric dental data and the second spline function at each of the crown centroids of the second spatial orientation of the crowns in the superficial dental data, a first vector tangent to the respective spline function, a second vector perpendicular to the respective spline function and passing through the dental arch centroid, and a third vector equal to the cross product of the first vector and the second vector. The three-dimensional affine transformation is based on the first vector, the second vector, and the third vector.

[0104] The technique shown in FIG. 15 includes transforming, by the computing device 102, e.g., the transformation module 130, each triangle vertex of the mesh defining the second spatial orientation of the tooth crown of the superficial dental data using a three-dimensional affine transformation (1412). In some embodiments, transforming each triangle vertex using the three-dimensional affine transformation may include multiple substeps. For example, the technique may include determining, by the computing device 102, e.g., the transformation module 130, a translation spline function that interpolates between translation components of the three-dimensional affine transformation. The technique may also include determining, by the computing device 102, e.g., the transformation module 130, a rotation spline function that interpolates between rotation components of the three-dimensional affine transformation. The technique may also include determining, by the computing device 102, e.g., the transformation module 130, a scaling spline function that interpolates between scaling components of the three-dimensional affine transformation. Alternatively, this technique may include determining, by the computing device 102, e.g., the transformation module 130, a higher-dimensional spline function that simultaneously interpolates between at least one of the translation, rotation, or scaling components of the 3D affine transformation. For example, a control point or keyframe in the spline function may be represented by any subset of values ​​in the transformation matrix that comprises the 3D affine transformation, not just a triplet for each of the translation or rotation values, e.g., (x, y, z) or (α, β, γ).

[0105] After determining the translation spline and the rotation spline, the technique may include, for each triangle vertex of the mesh defining the second spatial orientation of the crown of the superficial dental data, transforming the vertex to the closest point on a second spline function by the computing device 102, e.g., the transformation module 130. The technique may also include defining, by the computing device 102, e.g., the transformation module 130, a plane that passes through the closest point on the second spline function and is perpendicular to the second spline function. The technique may also include determining, by the computing device 102, e.g., the transformation module 130, a value of the second spline function at an intersection of the plane and the closest point on the second spline function. The technique may also include evaluating, by the computing device 102, e.g., the transformation module 130, the translation spline function and the rotation spline function at the value to determine at least one of a translation component, a rotation component, or a scaling component. The technique may also include defining, by computing device 102, e.g., transformation module 130, a vertex-specific 3D affine transformation that includes at least one of a translation component, a rotation component, or a scaling component. The technique may also include applying, by computing device 102, e.g., transformation module 130, the vertex-specific 3D transformation to the vertices.

[0106] In some embodiments, the combined dental data generated using the techniques illustrated in Figures 5-14 may be used to manufacture dental appliances.

[0107] FIG. 16 is a block diagram illustrating an exemplary computer environment 10 in which the clinic 14 and the manufacturing facility 20 communicate information throughout the manufacturing process of dental appliances 22 for the patient 12. The dental appliances 22 may include, for example, clear tray aligners, implants, prostheses, etc. Initially, an orthodontic practitioner at the clinic 14 generates one or more images of the patient 12's dental structure, using, for example, the first imaging device 106 and the second imaging device 108 ( FIG. 1 ), to generate volumetric and superficial dental structure data. To generate digital dental structure data 16, a computer must convert the raw data from the imaging system into a usable digital model using the techniques described above. Additionally, the computer may segment the dentition surface to generate one or more individual, movable 3D tooth object models representing each tooth. The computer may further separate these tooth models from the gums into separate objects. Segmentation may enable a user to characterize and manipulate the tooth arrangement as a set of individual objects. In some embodiments, a computer may obtain diagnostic information from these models, such as arch length, bite alignment, spacing between adjacent teeth, and even an American Board of Orthodontics (ABO) objective assessment. By replacing physical processes with digital processes, data acquisition and data manipulation steps can be performed in separate locations without the need to transport stone models or impressions from one location to another. Reducing or eliminating the need to transport physical objects can result in significant cost savings for both the customer and the manufacturer of customized appliances.

[0108] After generating the digital dental structure data 16, the clinic 14 may store the digital dental structure data 16 in a patient record in a database. The clinic 14 may, for example, update a local database having multiple patient records. Alternatively, the clinic 14 may remotely update a central database (optionally within the manufacturing facility 20) via the network 24. After storing the digital dental structure data 16, the clinic 14 electronically communicates the digital dental structure data 16 to the manufacturing facility 20. Alternatively, the manufacturing facility 20 may retrieve the digital dental structure data 16 from the central database. Alternatively, the manufacturing facility 20 may retrieve existing digital dental structure data 16 from a data source independent of the clinic 14.

[0109] The clinic 14 may also transmit prescription data 18, which conveys general information regarding the physician's diagnosis and treatment plan for the patient 12, to a manufacturing facility 20. The manufacturing facility 20 may be located at a different location or may be within the clinic 14. For example, each clinic 14 may function as a manufacturing facility 20 so that treatment planning and digital design can be performed entirely by a clinician or assistant using locally installed software in the clinical environment.

[0110] The manufacturing facility 20 utilizes the digital dental structure data 16 of the patient 12 to construct the dental appliances 22. Manufacturing may include 3D printing or other methods of additive manufacturing. 3D printers allow for the fabrication of intricate features of the dental appliances or physical representations of the patient 12's dental structure. In some embodiments, other methods of additive manufacturing may include, for example, thermoforming, 3D printing, and / or fused deposition modeling, which uses a 5-axis or 6-axis Cartesian robot or an articulated arm robot to mill the removable dental appliances and then dispense material onto the surfaces of the removable dental appliances. Manufacturing may also include post-processing, such as milling to remove uncured resin, remove support structures, or assemble various components, which may be necessary and could be performed in a clinical setting.

[0111] At some point thereafter, the manufacturing facility 20 transfers the dental appliances 22 to the clinic 14, or alternatively, directly to the patient 12. The patient 12 may return to the clinic 14 for periodic observations of the progress of treatment with the removable dental appliances 22. During such periodic observations, the clinician may arrange for the patient 12 to sequentially wear the removable dental appliances in the set of removable dental appliances 22 over time. The observations generally include a visual inspection of the patient's 12's teeth and may also include imaging to generate new digital dental structure data 16.

[0112] Various embodiments have been described. These and other embodiments are within the scope of the following claims.

[0113] "Adjacent teeth" refers to teeth that are within two teeth of the nearest pontic. For example, if the pontic is upper right central incisor 11 using the FDI two-digit notation, teeth 12, 13, 21, and 22 are considered adjacent teeth.

[0114] "Pontic" refers to an artificial tooth that replaces a missing natural tooth. Pontics can also be called units in some cases, which are removable restorative dental appliances.

[0115] "Removable dental appliances" refer to appliances that are removable from a patient's dentition and are used in orthodontic treatment. Examples of removable dental appliances include clear tray aligners.

[0116] A "removable restorative dental appliance" refers to a restoration for a patient's dentition that is removable from the dentition without tools. A removable restorative dental appliance can be a pontic (e.g., a dental bridge or partial denture) or a dental replacement incorporating a retainer. A removable restorative dental appliance can also be secured to an abutting tooth or implant.

[0117] "Retainer" refers to a dental appliance used to hold teeth in correct position, especially following orthodontic treatment.

[0118] "Spline function" refers to a wide range of functions used in applications requiring data interpolation and / or smoothing. Listing of Exemplary Embodiments 1. receiving, by a computing device, volumetric dental data indicative of a patient's three-dimensional subgingival dental structure; receiving, by a computing device, superficial dental data indicative of a three-dimensional superficial dental structure of the patient; segmenting, by a computing device, a first subset of volumetric dental data representing crowns of the patient's teeth from a second subset of volumetric dental data representing roots of the teeth, the first subset of volumetric dental data indicating a first spatial orientation of the crowns and the second subset of volumetric dental data indicating a spatial orientation of the roots; segmenting, by the computing device, a first subset of superficial dental data representing the dental crowns from a second subset of superficial dental data representing the patient's gingiva, wherein the first subset of superficial dental data indicates a second spatial orientation of the dental crowns and the second subset of superficial dental data indicates a spatial orientation of the gingiva; transforming, by the computing device, the first subset of superficial dental data indicative of the second spatial orientation of the crowns such that the second spatial orientation of the crowns is substantially aligned with the first spatial orientation of the crowns; generating combined dental data by replacing, with the computing device, a first subset of subgingival data indicative of a first spatial orientation of the tooth crown with a transformed first subset of superficial dental data indicative of a second spatial orientation of the tooth crown, and splicing the transformed first subset of superficial dental data indicative of the second spatial orientation of the tooth crown with a second subset of volumetric dental data representing the tooth root; outputting, by the computing device, image data based on the combined dental data for display. 2. The method of embodiment 1, wherein receiving the volumetric dental data includes receiving, by a computing device, the volumetric dental data from a cone beam computed tomography scanner or a magnetic resonance imaging scanner. 3. The method of embodiment 1 or 2, wherein receiving the superficial dental data includes receiving, by the computing device, the superficial dental data from an intraoral scanner. 4. The method of any one of embodiments 1-3, wherein the subgingival dental structure comprises at least one of the patient's maxilla, the patient's mandible, or a portion of the patient's skull. 5. The method of any one of embodiments 1 to 4, wherein the superficial dental data comprises a triangular mesh representing an optically visible surface of at least a portion of the patient's upper dental arch or the patient's lower dental arch. 6. The method of any one of embodiments 1 to 5, wherein the volumetric dental data comprises density-weighted point clouds resolving hard tissues of subgingival dental structures and soft tissues of subgingival dental structures, wherein the hard tissues comprise at least one of enamel, dentin, cementum, alveolar bone, or cortical bone, and wherein the soft tissues comprise at least one of hard palate, gingiva, tongue, oral mucosa, periodontal ligament, cartilage, muscle, or skin. 7. A method as described in any one of embodiments 1 to 6, wherein receiving the volumetric dental data further includes filtering, by the computing device, the volumetric dental data using at least one density threshold based on at least one density of at least one of hard tissue or soft tissue. 8. The method of embodiment 7, wherein the at least one density threshold comprises upper and lower density thresholds of at least one of enamel, dentin, cementum, alveolar bone, cortical bone, hard palate, gingiva, tongue, oral mucosa, periodontal ligament, cartilage, muscle, or skin. 9. Segmenting a first subset of volumetric dental data from a second subset of volumetric dental data; segmenting, by a computing device, a first spatial orientation of the crown from a spatial orientation of the root by combining points of the point cloud that are indicative of at least one of enamel, dentin, cementum, or a restorative material; 9. A method according to any one of embodiments 1 to 8, comprising determining, by a computing device, a triangular vertex mesh that defines an exterior surface of the combined points. 10. The method is defining, by the computing device, a first group including a first subset of the volumetric dental data and a portion of the second subset of the volumetric dental data; The method of any one of embodiments 1 to 9, further comprising: defining, by a computing device, a second group including a portion of the first subset of superficial dental data, wherein the portion of the first subset of superficial dental data corresponds to a portion of the first subset of volumetric dental data. 11. The method of embodiment 10, wherein the first group includes the crowns of the maxillary or mandibular dental arch of the volumetric dental data and the corresponding roots of the maxillary or mandibular dental arch of the volumetric dental data, and the second group includes the crowns of the maxillary or mandibular dental arch of the superficial dental data. 12. The method of embodiment 10 or 11, wherein the first group includes a plurality of first groups, each of which includes at least two dental crowns of the first subset of volumetric dental data and at least two corresponding dental roots of the second subset of volumetric dental data, and the second group includes a plurality of second groups, each of which includes at least two dental crowns of the first subset of superficial dental data. 13. A method according to any one of embodiments 1 to 12, wherein transforming the second spatial orientation of the crown of the superficial dental data includes, by a computing device, at least one of translating or rotating the second spatial orientation of the crown of the superficial dental data to substantially align it with the first spatial orientation of the crown of the volumetric dental data. 14. A method according to any one of embodiments 1 to 13, wherein the transforming comprises applying a plurality of linear transforms to individual segments of the corresponding portion of the second dental data, or applying a non-linear continuous transform to the corresponding portion of the second dental data. 15. Transforming a second spatial orientation of the crown of the superficial dental data determining, by the computing device, at least one of a dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structural landmarks, one or more mesh vertices, and one or more mesh triangles based on the first spatial orientation of the dental crowns of the volumetric dental data; determining, by the computing device, at least one of a dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structural landmarks, one or more mesh vertices, and one or more mesh triangles based on a second spatial orientation of the crowns of the superficial dental data; The method of any one of embodiments 1 to 14, comprising: translating or rotating, by a computing device, at least one of the dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structural landmarks, one or more mesh vertices, and one or more mesh triangles of a second spatial orientation of the crown of the superficial dental data in three-dimensional space to substantially align it with at least one of the dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structural landmarks, one or more mesh vertices, and one or more mesh triangles of a first spatial orientation of the crown of the volumetric dental data. 16. Transforming a second spatial orientation of the crown of the superficial dental data determining, by a computing device, one or more crown centroids of a first spatial orientation of the crowns of the volumetric dental data and a second spatial orientation of the crowns of the superficial dental data; determining, by the computing device, a translational movement between one or more crown centroids of a first spatial orientation of the crowns of the volumetric dental data and one or more corresponding crown centroids of a second spatial orientation of the crowns of the superficial dental data; translating, by the computing device, each triangle vertex of the mesh that defines a second spatial orientation of the crown of the superficial dental data by a translational movement; determining, by the computing device, a horizontal rotation angle α between a first vector between a first crown and a second crown of a first spatial orientation of the crowns of the volumetric dental data and a second vector between a third crown and a fourth crown of a second spatial orientation of the crowns of the superficial dental data, wherein the first crown corresponds to the third crown and the second crown corresponds to the fourth crown; rotating, by the computing device, each triangle vertex of the mesh defining the third crown by a horizontal rotation angle α using the centroid of the third crown as a center of rotation; determining, by the computing device, a vertical rotation angle θ between a third vector between the first crown and the centroid of the first spatial orientation of the crown of the volumetric dental data and a fourth vector between the third crown and the centroid of the second spatial orientation of the crown of the superficial dental data; 15. The method of any one of embodiments 1 to 14, further comprising: rotating, by a computing device, each triangle vertex of the mesh defining the third crown by a vertical rotation angle θ using the center of gravity of the third crown as the rotation center. 17. The method of embodiment 16, wherein transforming the second spatial orientation of the crowns of the superficial dental data further comprises repeating horizontal rotation and vertical rotation for each crown of the second spatial orientation of the crowns of the superficial dental data. 18. Transforming a second spatial orientation of the crown of the superficial dental data determining, by a computing device, a first centroid for each first group of the plurality of first groups and a second centroid for each second group of the plurality of second groups; determining, by a computing device, a translational movement between each first centroid and a corresponding second centroid; translating, by a translation movement, each triangle vertex of each mesh defining each second group of the plurality of second groups; determining, by the computing device, a vertical rotation angle θ between a first vector between each first centroid and the centroids of the plurality of first groups and a second vector between each second centroid and the centroids of the plurality of second groups; A method according to any one of embodiments 1 to 14, further comprising: rotating, by a computing device, each triangle vertex of each mesh defining each second group among the plurality of second groups by a vertical rotation angle θ using the respective second centroid as a rotation center. 19. The method of embodiment 18, wherein transforming the second spatial orientation of the crowns of the superficial dental data further comprises repeating the vertical rotation for each second group of the plurality of second groups. 20. Transforming a second spatial orientation of the crown of the superficial dental data determining, by a computing device, a first centroid for each first group of the plurality of first groups and a second centroid for each second group of the plurality of second groups; determining, by a computing device, a degree of collinearity of each of the first centroid and the second centroid; determining, by a computing device, whether each respective degree of collinearity is greater than a threshold; adjusting, by the computing device, an orientation of each respective second group of the plurality of second groups as a function of the original orientation of the respective second group, as well as the orientation of the respective second group and an orientation of at least one other second group of the plurality of second groups; Dividing, by the computing device, each respective second group of the plurality of second groups into at least two subgroups; 15. The method of any one of embodiments 1 to 14, further comprising iteratively determining the center of gravity, determining the degree of collinearity, adjusting the orientation, and dividing each respective subgroup until each subgroup contains two tooth crowns. 21. Transforming a second spatial orientation of the crown of the superficial dental data determining, by a computing device, a dental arch centroid of the volumetric dental data and the superficial dental data; determining, by the computing device, a crown centroid for each crown of a first spatial orientation of the crown of the volumetric dental data and a second spatial orientation of the crown of the superficial dental data; translating, by the computing device, each triangle vertex of the mesh defining the second spatial orientation of the crown of the superficial dental data by a translational movement between a crown centroid of the first spatial orientation of the crown of the volumetric dental data and a corresponding crown centroid of the second spatial orientation of the crown of the superficial dental data; determining, by a computing device, a first spline function passing through the crown centroids of the first spatial orientation of the crowns of the volumetric dental data and a second spline function passing through the crown centroids of the translated second spatial orientation of the crowns of the superficial dental data; determining, by a computing device, a three-dimensional affine transformation from the second spline function to the first spline function; 15. The method of any one of embodiments 1 to 14, further comprising: transforming, by a computing device, each triangle vertex of the mesh that defines a second spatial orientation of the crown of the superficial dental data using a three-dimensional affine transformation. 22. Determining a 3D affine transformation is determining, by the computing device, for each of the first spline functions at each of the crown centroids of the first spatial orientation of the crowns of the volumetric dental data and the second spline function at each of the crown centroids of the second spatial orientation of the crowns of the superficial dental data, a first vector tangent to the respective spline function, a second vector perpendicular to the respective spline function and passing through the dental arch centroid, and a third vector equal to the cross product of the first vector and the second vector; 22. The method of embodiment 21, comprising determining, by the computing device, a three-dimensional affine transformation based on the first vector, the second vector, and the third vector. 23. Transforming each triangle vertex of a mesh that defines a second spatial orientation of the crown of the superficial dental data using a three-dimensional affine transformation; determining, by a computing device, a translation spline function that interpolates between translation components of the three-dimensional affine transformation; determining, by a computing device, a rotational spline function that interpolates between rotational components of the three-dimensional affine transformation; For each triangle vertex of the mesh defining a second spatial orientation of the crown of the superficial dental data: projecting, by a computing device, the vertices onto the closest points on the second spline function; defining, by a computing device, a plane that passes through the closest point on the second spline function and is perpendicular to the second spline function; determining, by the computing device, a value of the second spline function at an intersection of the plane and a closest point on the second spline function; evaluating, by a computing device, translation and rotation spline functions at the values ​​to determine translation and rotation components; defining, by a computing device, a vertex-specific 3D affine transformation including translational and rotational components; applying, by a computing device, a vertex-specific three-dimensional transformation to the vertices; 23. The method of embodiment 21 or 22, comprising: 24. Receiving, by a computing device, first dental data indicative of a first three-dimensional dental structure of the patient; receiving, by the computing device, second dental data indicative of a second three-dimensional dental structure of the patient; segmenting, by the computing device, a first subset of the first dental data from a second subset of the first dental data, wherein at least a portion of the second dental data corresponds to the first subset of the first dental data; transforming, by the computing device, the corresponding portion of the second dental data to substantially align with the first dental data; generating combined dental data by replacing, with the computing device, a first subset of the first dental data with a transformed corresponding portion of the second dental data and splicing the transformed second dental data with a second subset of the second dental data; outputting, by the computing device, image data based on the combined dental data for display. 25. The method of embodiment 24, wherein the first three-dimensional dental structure includes a removable restorative dental appliance worn by the patient, and in the second three-dimensional dental structure, the removable restorative dental appliance is not worn by the patient. 26. The method of embodiment 24, wherein the second three-dimensional dental structure includes a removable restorative dental appliance worn by the patient, and in the first three-dimensional dental structure, the removable restorative dental appliance is not worn by the patient. 27. The method of embodiment 25, wherein the first subset of the first dental data includes volumetric dental data of a removable restorative dental appliance, and the second subset of the first dental data includes volumetric dental data of the patient's dentition. 28. The method of embodiment 25, wherein at least one action is performed in response to generating the combined dental data. 29. The method of any one of embodiments 1 to 28, wherein transforming includes applying a plurality of linear transformations to individual segments of the corresponding portion of the first dental data. 30. The method of any one of embodiments 1 to 29, wherein transforming includes applying a nonlinear continuous transformation to the corresponding portion of the first dental data. 31. The method of embodiment 30, wherein the nonlinear continuous transformation comprises a spline function. 32. The method of any one of embodiments 1-31, wherein the removable restorative dental appliance comprises a pontic. 33. The method of any one of embodiments 1-32, wherein the removable restorative dental appliance comprises a retainer. 34. The method of embodiment 33, wherein the removable restorative dental appliance is a dental bridge (fixed partial denture) including a fixed portion. 35. The method of embodiment 33, wherein the patient's three-dimensional (3D) dental structure further comprises at least some portion of a tooth root, gingiva, periodontal ligament (PDL), alveolar process, or cortical bone. 36. Accessing, by a computing device, a digital representation of the combined dental data; determining, by a computing device, a size and shape of a removable dental appliance for the patient based on a treatment plan, the treatment plan excluding a segmented region including at least a portion of the removable restorative dental appliance from tooth position adjustments of adjacent teeth, the removable dental appliance comprising: an appliance body configured to at least partially surround and form a plurality of teeth of the patient's dental arch, the appliance body including a unitary material defining a shell shaped to receive at least one tooth of the patient; determining the size and shape of the removable dental appliance, including the location, size, and shape of the shell; 36. The method of any one of embodiments 1 to 35, further comprising: transmitting, by a computing device, a representation of the removable dental appliance to a computer-aided manufacturing system. 37. The removable restorative dental appliance is a partial denture including a pontic surrounded by a denture base, the denture base conforming to the patient's gums or bone ridge; 37. The method of embodiment 36, wherein determining the size and shape of the removable dental appliance incorporates the dimensions of the denture base material. 38. The method according to embodiment 37, wherein, except for the substrate (sub), no repositioning force is applied to the pontic, but forces are applied to the adjacent teeth. 39. The method according to embodiment 37, wherein the treatment plan does not use removable restorative dental appliances as anchors that affect tooth positioning. 40. A method according to any one of embodiments 36 to 39, wherein determining the dimensions and shape of the removable dental appliance by a computing device includes accepting input from a user, the input affecting at least one of the dimensions and shape. 41. A method according to any one of embodiments 36 to 40, wherein determining the dimensions and shape of the removable dental appliance by a computing device includes automatically determining at least one of the dimensions and shape. 42. A method according to any one of embodiments 36 to 41, wherein determining the dimensions and shape of the removable dental appliance by a computing device includes presenting a representation of the removable dental appliance to a user for review. 43. A method according to any one of embodiments 36 to 42, wherein transmitting a representation of the removable dental appliance includes transmitting a digital model of the removable dental appliance from a computing device to a computer-aided manufacturing system, and manufacturing at least a portion of the removable dental appliance in the computer-aided manufacturing system according to the digital model from the computing device. 44. The method of embodiment 43, wherein the computer-aided manufacturing system includes a 3D printer, and at least a portion of the removable dental appliance is formed using the 3D printer. 45. The method of any one of embodiments 36 to 44, further comprising determining, by a computing device, the dimensions and shape of each of a set of ordered removable orthodontic appliances for the patient, wherein the removable dental appliance is one of the set of ordered removable orthodontic appliances for the patient, and each removable dental appliance in the set of ordered removable orthodontic appliances is configured to incrementally reposition the patient's teeth to a more advanced position than any one of the previous removable dental appliances in the set of removable orthodontic appliances. 46. ​​The method of claim 45, wherein the set of ordered removable orthodontic appliances is configured to avoid rearranging any units from the segmented region. 47. Determining the size and shape of the removable dental appliance by the computing device includes selecting the size and shape of the removable dental appliance according to a set of predefined design constraints by the computing device, wherein the set of predefined design constraints includes: the minimum and maximum local forces exerted on one or more teeth or attachments of a patient when the removable dental appliance is worn by the patient; the minimum and maximum rotational forces applied to one or more teeth or attachments of the patient when the removable dental appliance is worn by the patient; the maximum force applied to any unit from a segmented area of ​​the removable dental appliance; the minimum and maximum translational forces exerted on one or more teeth or attachments of the patient when the removable dental appliance is worn by the patient; the minimum and maximum total forces exerted on one or more teeth or attachments of a patient when the removable dental appliance is worn by the patient; and and a minimum and maximum stress or strain exerted on the removable dental appliance when worn by a patient. 48. The method of any one of embodiments 36 to 47, further comprising selecting a material for the removable dental appliance by a computing device. 49. A method according to any one of embodiments 45 to 48, wherein determining the dimensions and shape of the removable dental appliance by a computing device includes selecting a thickness of at least one portion of the appliance body so as to provide suitable rigidity for repositioning one or more teeth of the patient from an initial position of the one or more teeth to an adjusted position when the removable dental appliance is worn by the patient. 50. Determining, by the computing device, the size and shape of the removable dental appliance includes modifying the initial position of one or more teeth of the patient (except for the segmented regions and where the anchorage is removed from the patient's teeth) to generate a modified dental structure; 50. The method of any one of embodiments 36 to 49, wherein the modified dental structure represents a gradual repositioning of one or more teeth of the patient compared to the initial position of the one or more teeth of the patient, and the size and shape of the removable dental appliance are adapted to the modified dental structure. 51. The method of any one of embodiments 36-50, wherein the shell defines a void within the shell and includes a surface shaped to receive at least one tooth in a desired position. 52. The method of any one of embodiments 36-51, wherein the computing device comprises a plurality of computing devices operably connected via one or more computer networks. 53. A computing device including a processor and a memory for storing instructions, which, when executed by the processor, configure an appliance to perform a method described in embodiments 24 to 52. 54. A computing device, comprising: a processor; and a memory for storing instructions, the instructions, when executed by the processor, receiving first dental data indicative of a first three-dimensional dental structure of the patient; receiving second dental data indicative of a second three-dimensional dental structure of the patient; segmenting the first subset of the first dental data from the second subset of the first dental data such that at least a portion of the second dental data corresponds to the first subset of the first dental data; transforming the corresponding portion of the second dental data to substantially align with the first dental data; replacing a first subset of the first dental data with a transformed corresponding portion of the second dental data and splicing the transformed second dental data onto a second subset of the second dental data to generate combined dental data; outputting image data for display based on the combined dental data. 55. The command is receiving, by a computing device, a digital representation of the combined dental data; determining, by a computing device, a size and shape of a removable dental appliance for the patient based on a treatment plan, the treatment plan excluding a segmented region including at least a portion of the removable restorative dental appliance from tooth position adjustments of adjacent teeth, the removable dental appliance comprising: an appliance body configured to at least partially surround and form a plurality of teeth of the patient's dental arch, the appliance body including a unitary material defining a shell shaped to receive at least one tooth of the patient; determining the size and shape of the removable dental appliance, including the location, size, and shape of the shell; transmitting, by a computing device, a representation of the removable dental appliance to a computer aided manufacturing system; 55. The computing device of embodiment 54, further configured to: 56. A non-transitory computer-readable storage medium storing computer system executable instructions, the computer system executable instructions, when executed, configuring a processor to perform a method according to any one of embodiments 1 to 53. [Explanation of symbols]

[0119] 314...bone, 316...tooth root, 402...tooth crown, 600...digital image.

Claims

1. receiving, by a computing device, volumetric dental data indicative of a patient's three-dimensional subgingival dental structure; receiving, by the computing device, superficial dental data indicative of a three-dimensional superficial dental structure of the patient; segmenting, with the computing device, a first subset of the volumetric dental data representing crowns of the patient's teeth from a second subset of the volumetric dental data representing roots of the teeth, the first subset of the volumetric dental data representing a first spatial orientation of the crowns and the second subset of the volumetric dental data representing a spatial orientation of the roots; segmenting, by the computing device, a first subset of the superficial dental data representing the tooth crowns from a second subset of the superficial dental data representing the patient's gingiva, wherein the first subset of the superficial dental data indicates a second spatial orientation of the tooth crowns and the second subset of the superficial dental data indicates a spatial orientation of the gingiva; transforming, by the computing device, the first subset of superficial dental data indicating the second spatial orientation of the crowns such that the second spatial orientation of the crowns is substantially aligned with the first spatial orientation of the crowns, wherein transforming the first subset of superficial dental data comprises: determining, by the computing device, one or more first centroids based on the volumetric dental data of one or more crowns in the first subset of volumetric dental data and one or more second centroids based on the superficial dental data of one or more crowns in the first subset of superficial dental data, wherein each of the one or more second centroids corresponds to a respective first centroid; determining, by the computing device, a translation between each first centroid and the corresponding second centroid; translating each triangle vertex of each mesh defining each tooth crown in the surface dental data by the determined translation; determining, by the computing device, one or more rotation angles, wherein the one or more rotation angles are one or more horizontal rotation angles or one or more vertical rotation angles, and determining the one or more rotation angles is performed by at least one of the following (a) and (b): (a) determining a horizontal rotation angle between a first vector defined between a centroid of a crown of a first tooth and a centroid of a crown of a second tooth derived from the volumetric dental data and a second vector defined between a centroid of a crown of the first tooth and a centroid of a crown of the second tooth derived from the superficial dental data; or (b) determining one or more rotation angles, including at least one of: a third vector defined between a centroid of a crown of a first tooth derived from the volumetric dental data and a dental arch centroid; and a fourth vector defined between a centroid of a crown of the first tooth derived from the superficial dental data and a dental arch centroid. rotating, by the computing device, each triangle vertex of each mesh defining each tooth crown in the superficial dental data by the one or more rotation angles using the respective second centroids as rotation centers; transforming the first subset of the superficial dental data, generating combined dental data by replacing, with the computing device, the first subset of subgingival data representing the first spatial orientation of the dental crown with the transformed first subset of superficial dental data representing the second spatial orientation of the dental crown and splicing the transformed first subset of superficial dental data representing the second spatial orientation of the dental crown with the second subset of volumetric dental data representing the root of the tooth; outputting, by the computing device, image data based on the combined dental data for display.

2. Transforming the first subset of the superficial dental data includes: determining, by the computing device, at least one of a dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structural landmarks, one or more mesh vertices, and one or more mesh triangles as the one or more first centroids based on the first spatial orientation of the dental crowns of the volumetric dental data; 2. The method of claim 1, further comprising: determining, by the computing device, at least one of a dental arch centroid, one or more dental arch segment centroids, one or more tooth centroids, one or more crown centroids, one or more dental structural landmarks, one or more mesh vertices, or one or more mesh triangles as the one or more second centroids based on the second spatial orientation of the crowns of the superficial dental data.

Images