Method and system for orthodontic treatment planning

Abstract

A method for planning orthodontic treatment for a patient includes: receiving three-dimensional intraoral surface scan data of the patient's dentition; receiving three-dimensional volume scan data of the patient's dentition; and superimposing the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis. The method also includes: determining a center of rotation of the at least one tooth for use in planning orthodontic treatment, wherein the center of rotation is defined as a point in the integrated patient model located at a predetermined distance from the base of the root to the tip of the root along the longitudinal axis of the at least one tooth.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application serial number 62 / 824,153 filed on March 26, 2019, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates generally to the field of orthodontic treatment planning. Background Art

[0004] Orthodontics is a specialty of dentistry that seeks to correct improperly positioned teeth and jaws of a patient, such as for health and / or cosmetic reasons. Typically, orthodontic treatment utilizes the application of external forces to gradually move one or more teeth from their original improper position to a desired position. One conventional orthodontic treatment involves bonding brackets to the surfaces of the teeth and gradually adjusting wires attached to the brackets to push the teeth into the desired position and orientation. Another conventional orthodontic treatment involves wearing clear appliance trays having tooth-receiving cavities to gradually move the teeth toward the final position and orientation.

[0005] Planning such orthodontic treatment includes obtaining a physical model and / or a digital model of the patient's dentition, and using such models to generate a proposed treatment path for each tooth to be moved. For example, a physical model of the patient's dentition may be obtained by mold impression, while a digital model may be obtained by scanning the patient's dentition (and / or a physical model of the patient's dentition) with a scanning device. However, such modeling methods are limited in the amount of patient information that may be obtained, resulting in inaccurate treatment plans and longer overall treatment times. Therefore, there is a need for improved methods and systems for orthodontic treatment planning. Summary of the invention

[0006] In general, a method for planning orthodontic treatment for a patient includes: receiving three-dimensional intraoral surface scan data of the patient's dentition; receiving three-dimensional volume scan data of the dentition; superimposing the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis; and determining a rotation center of the at least one tooth for use in planning orthodontic treatment, wherein the rotation center is defined as a point in the integrated patient model located at a predetermined distance from the base of the root to the tip of the root along the longitudinal axis of the at least one tooth. For example, the determined rotation center of the at least one tooth may be defined as a point located between about one-third and about one-half (e.g., about one-third) of the distance between the base of the root and the tip of the root along the longitudinal axis. The root may be, for example, an anatomical root (e.g., extending from the dentin-enamel junction (DEJ) of the tooth to the root apex of the tooth) or a functional root (e.g., extending from the crestal bone height of the tooth to the root apex of the tooth). In some variations, the intraoral surface scan data may include optical color scan data and / or the volume scan data may include X-ray scan data, such as CBCT.

[0007] In some variations, superimposing the intraoral surface scan data and the volume scan data includes registering the intraoral surface scan data with the volume scan data. For example, such registration may be aligned to one or more fiducials (e.g., anatomical landmarks, artificial fiducials such as radiopaque markers, etc.). In some variations, the three-dimensional volume scan data includes data of the dentition and the craniofacial structure of the patient.

[0008] In general, a system for planning orthodontic treatment for a patient includes at least one memory device configured to receive and store three-dimensional intraoral surface scan data of the patient's dentition, and three-dimensional volume scan data of the dentition. The system may also include at least one processor configured to superimpose the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis. The system may include: one or more displays configured to display the integrated patient model; and / or a user interface for navigating the integrated patient model. The processor may also be configured to determine a rotation center of the at least one tooth for planning orthodontic treatment, wherein the rotation center is defined as a point in the integrated patient model located at a predetermined distance from the base of the root to the tip of the root along the longitudinal axis of the at least one tooth. For example, the determined rotation center of the at least one tooth may be defined as a point located along the longitudinal axis between about one-third and about one-half (e.g., about one-third) of the distance between the base of the root and the tip of the root. The root may be, for example, an anatomical root (e.g., extending from the dentin-enamel junction (DEJ) of the tooth to the root apex of the tooth) or a functional root (e.g., extending from the crestal bone height of the tooth to the root apex of the tooth). In some variations, the intraoral surface scan data may include optical color scan data, and / or the volume scan data may include X-ray scan data, such as CBCT.

[0009] In some variations, the processor may be configured to register the intraoral surface scan data and the volume scan data when superimposing the intraoral surface scan data and the volume scan data. For example, such registration may be aligned to one or more fiducials (e.g., anatomical landmarks, artificial fiducials such as radiopaque markers, etc.). In some variations, the three-dimensional volume scan data includes data of the dentition and the craniofacial structures of the patient.

[0010] In general, a method for planning orthodontic treatment for a patient comprises: receiving three-dimensional intraoral surface scan data of the patient's dentition; receiving three-dimensional volume scan data of the patient's dentition and craniofacial structure; superimposing the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis; automatically separating the root of the at least one tooth from a portion of the integrated patient model surrounding the root; and determining a center of rotation of the at least one tooth for use in planning orthodontic treatment. In some variations, the intraoral surface scan data may include optical color scan data, and / or the volume scan data may include X-ray scan data, such as CBCT.

[0011] In some variations, a center of rotation of the at least one tooth may be automatically determined (e.g., by a computing device) based on the integrated patient model resulting from the superposition of the scan data. For example, the process of determining the center of rotation may involve automatically separating (in the integrated patient model) a root of the at least one tooth, a periodontal ligament associated with the at least one tooth, and / or a bone surrounding the at least one tooth based at least in part on voxel density. For example, in some variations, automatically separating the root of the at least one tooth may include determining a voxel density of the at least one tooth in the integrated patient model, and comparing the determined voxel density to a predetermined threshold voxel density for the at least one tooth. As another example, automatically separating the root of the at least one tooth may include: determining a first voxel density of the at least one tooth in the integrated patient model; determining a second voxel density of at least one of: one or more periodontal ligaments associated with the at least one tooth in the integrated patient model, and bone surrounding the at least one tooth in the integrated patient model; and comparing a difference between the first voxel density and the second voxel density to a predetermined threshold difference.

[0012] Additionally, determining the center of rotation may further include determining a volume of the at least one tooth and determining the longitudinal axis of the at least one tooth in the integrated patient model. In some variations, the determined center of rotation of the at least one tooth may be defined as a point located between about one third and about one half of the distance from the base of the root to the tip of the root along the longitudinal axis. The center of rotation may then be used to plan orthodontic treatment, such as orthodontic treatment via a plurality of appliance trays having tooth receiving cavities, wherein each appliance tray corresponds to a respective tooth arrangement, such that the series of appliance trays progressively move the teeth in a treatment path according to the center of rotation of the natural movement of the teeth.

[0013] In general, a system for planning orthodontic treatment for a patient includes at least one memory device configured to receive and store three-dimensional intraoral surface scan data of the patient's dentition and three-dimensional volume scan data of the patient's dentition and craniofacial structure. The system may also include at least one processor configured to superimpose the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis. The system may include: one or more displays configured to display the integrated patient model; and / or a user interface for navigating the integrated patient model. The processor may also be configured to automatically separate the root of the at least one tooth from a portion of the integrated patient model surrounding the root, and determine a center of rotation of the at least one tooth for use in planning orthodontic treatment. In some variations, the intraoral surface scan data may include optical color scan data, and / or the volume scan data may include X-ray scan data, such as CBCT.

[0014] In some variations, the center of rotation of the at least one tooth may be automatically determined (e.g., by a computing device) based on the integrated patient model resulting from the superposition of the scan data. For example, the processor may be configured to determine the center of rotation of the at least one tooth at least in part by automatically separating (in the integrated patient model) the root of the at least one tooth, the periodontal ligament associated with the at least one tooth, and the bone surrounding the at least one tooth based at least in part on voxel density. In addition, the processor may be configured to automatically determine the volume of the at least one tooth and determine the longitudinal axis of the at least one tooth in the integrated patient model. In some variations, the determined center of rotation of the at least one tooth may be defined as a point along the longitudinal axis that is between about one-third and about one-half of the distance from the base of the root to the tip of the root. The center of rotation can then be used to plan orthodontic treatment, such as orthodontic treatment performed via multiple brace trays having tooth receiving cavities, wherein each brace tray corresponds to a respective tooth arrangement, such that the series of brace trays incrementally move the teeth in a treatment path according to the center of rotation of the natural movement of the teeth. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram depicting a variation of a method for orthodontic treatment planning.

[0016] Figure 2 is a schematic diagram depicting a variation of a system for orthodontic treatment planning.

[0017] Figure 3 is a schematic diagram depicting a variation of determining the center of rotation of a tooth in an integrated patient model.

[0018] Figure 4 An exemplary raw surface scan image based on intra-oral surface scan data of a patient's dentition is depicted.

[0019] Figure 5 Depicted Figure 4 An exemplary prepared surface scan model based on the original surface scan image depicted in FIG.

[0020] Figure 6 An exemplary volume scan image of a patient's dentition is depicted.

[0021] Figure 7 An exemplary segmented intra-oral surface scan model of a patient's dentition is depicted.

[0022] Figure 8 A segmented and enveloped scanned model of the intraoral surface depicting the patient's dentition.

[0023] Fig. 9 An exemplary integrated patient model incorporating intra-oral surface scan data and volume scan data of the patient's dentition is depicted.

[0024] Fig. 10A is an illustrative diagram depicting a tooth and its anatomical roots. Fig. 10B is a schematic diagram depicting the center of resistance of a tooth based on its anatomical root.

[0025] Fig.11A is a schematic diagram depicting a normal tooth and its functional root. Fig. 11B is an illustrative diagram depicting the center of resistance of a tooth determined based on its functional root. Fig. 11C is a projection view of a tooth that is Fig. 11B The movement near the center of resistance shown is tilted in the predicted rotation due to the forces applied to the tooth.

[0026] Fig. 12A is a schematic diagram depicting an abnormal tooth and its functional root. Fig. 12B is an illustrative diagram depicting the center of resistance of a tooth based on its functional rate determination. Fig. 12C is a projection view of a tooth that is Fig. 12B The movement near the center of resistance shown is tilted in the predicted rotation due to the forces applied to the tooth.

[0027] Fig.13 is an illustrative diagram depicting a user-selected center of resistance for a tooth.

[0028] Fig.14 Depicted are the longitudinal axis and planned rotation of an exemplary tooth generated based on analysis of only intraoral surface scan data.

[0029] Fig.15 Depicted Fig.16 The longitudinal axis of an exemplary tooth and the planned rotation are superimposed on the volume scan image.

[0030] Fig.16 The longitudinal axis of an exemplary tooth is depicted based on analysis of an integrated patient model including intraoral surface scan data and volume scan data.

[0031] Fig.17 The longitudinal axis and planned rotation of an exemplary tooth as shown in FIG. 18 are depicted.

[0032] Fig.18A Describes Fig.14 and Fig.17 Superposition of the longitudinal axis of an exemplary tooth and the planned rotation is shown. Fig.18B is summarized as Fig.14 and Fig.15 A table showing the errors in the determined longitudinal axis is shown. DETAILED DESCRIPTION

[0033] Non-limiting examples of various aspects and variations of the invention are described herein and illustrated in the accompanying drawings.

[0034] Methods and systems for improving the accuracy of orthodontic treatment planning to move teeth are described herein. Specifically, the methods and systems described herein enable determination of the root orientation of a tooth and the corrected center of rotation of the tooth. The center of rotation of the tooth can then be used in treatment planning as the basis for a treatment path along the natural axis of movement, thereby achieving significant clinical benefits such as by reducing the total treatment time.

[0035] Methods used in orthodontic treatment planning

[0036] In general, if Figure 1 As shown in , in some variations, a method 100 for planning orthodontic treatment for a patient includes: receiving three-dimensional intraoral surface scan data of the patient's dentition 110, receiving three-dimensional volume scan data of the patient's dentition 120, superimposing the intraoral surface scan data and the volume scan data to generate an integrated patient model 130; and determining a center of rotation of at least one tooth for use in planning orthodontic treatment 140. In some variations, the integrated patient model includes a root of at least one tooth having a longitudinal axis, and the center of rotation may be defined as a point in the integrated patient model located at a predetermined distance from the base of the root to the tip of the root along the longitudinal axis of the at least one tooth.

[0037] Scan Data

[0038] like Figure 2 As shown in the schematic diagram of , a first scan data set (e.g., intraoral surface scan data 212) and a second scan data set (e.g., volume scan data 222) can be generated by one or more scanning devices that are configured to obtain anatomical imaging data of a patient. For example, an intraoral scanning device 210 can be used by a practitioner or other user to obtain image data (e.g., optical color scan data) representing the outer surface of a patient's dentition (e.g., crowns, gums, etc.). The intraoral scanning device can be, for example, a handheld scanner that emits light toward the patient's dentition when the scanner is manipulated within the patient's oral cavity. The emitted light is reflected from the surface of the patient's dentition, and the reflected light is captured by the intraoral scanner, and the reflected light is subsequently analyzed to convert the reflected light data into surface imaging data. An exemplary intraoral scanner suitable for obtaining three-dimensional intraoral surface scan data 212 is a CS 3600 intraoral scanner available from CARESTREAM DENTAL LLC (Atlanta, Georgia, USA). However, any suitable intraoral scanner can be used to obtain such intraoral surface scan data 212.

[0039] In general, the digitized surface of a patient's dentition obtained from an intraoral surface scan can be used to create one or more patient-customized orthodontic appliances (e.g., using computer-aided design and computer-aided manufacturing (CAD / CAM) techniques), which can, for example, be used to apply forces to the teeth and induce controlled orthodontic tooth movement (OTM). Accurate surface scan data of the patient's teeth enables such appliances to have a predictable, tight fit with the unique curvature of the teeth. In addition, precisely manipulating the accurate intraoral surface scan data allows the creation of orthodontic appliances to induce effective OTM.

[0040] Figure 4 An exemplary raw surface scan image based on intraoral surface scan data of the patient's upper dentition 410 and lower dentition 420 is shown. Figure 4 As shown, while intraoral surface scan data can provide information about the external form of the crown and at least a portion of the gums, intraoral surface scan data does not provide direct information about certain other tooth structures, such as the length and size of the underlying root and bone. In addition, the raw surface scan data can be manipulated to form a prepared surface scan model, such as Figure 5 Model 500 is shown. For example, the scan image may be trimmed to include only relevant scan data and / or placed onto a template jaw base model, etc.

[0041] The volume scan data 222 may be obtained by a volume scanner 220. In some variations, the volume scanner may provide three-dimensional X-ray imaging (e.g., cone beam computed tomography (CBCT)) of the dentition (e.g., crowns, gums, root structures) and craniofacial features (e.g., bones). Specifically, the volume scanner may be configured to provide detailed information about the root orientation of each tooth. An exemplary CBCT X-ray scanner suitable for obtaining the three-dimensional volume scan data 222 is the RAYSCAN α imaging device available from RAYCOMPANY (RAY AMERICA, Inc., Fort Lee, New Jersey, USA). However, any suitable extraoral scanner that provides volumetric information of the dentition and craniofacial features may be used to obtain the volume scan data 222.

[0042] In general, volume scan data obtained from an ionizing or non-ionizing volume scanner can be used to identify patient anatomical features, such as bone structure, tooth crowns and roots, and / or pathology of the craniofacial region, as well as to measure or otherwise quantify other patient characteristics, such as airway volume, facial phenotype, and / or jaw malocclusion. For example, as depicted in FIG. Figure 6 As shown, the volume scan data can provide the volume, length and / or morphology of the tooth root. As further described below, this information about the tooth root can improve the modeling of orthodontic tooth movement by, for example, allowing the actual center of resistance and long axis of each tooth for rotation within the patient's jaw to be detailed.

[0043] Model segmentation

[0044] In some embodiments, discrete portions of the model corresponding to surface scan data and / or the model corresponding to volume scan data may be identified during the model segmentation process. For example, different portions of a model (where the different portions correspond to different anatomical features) may be segmented. For example, different teeth in a model may be segmented so that each tooth in isolation can be independently selected, observed, and / or manipulated. In some embodiments, at least the root structure of at least one tooth in the model may be separated from the rest of the model (as discrete, identifiable volumes). Additionally or alternatively, the model may be segmented to separate other anatomical features, such as the crown of each tooth, the gums, the periodontal ligament, and the bone. For example, Figure 7 A segmented model 700 corresponding to intraoral surface scan data is depicted in which individual teeth (e.g., T1 and T2) are segmented as separate structures, and the teeth are further segmented relative to the gums (G). In some variations, for example, the model segmentation may also include isolating one or more anatomical features, such as to enable the isolated features to be individually selected and displayed. For example, Figure 8A portion of an intraoral surface scan model is depicted, including a crown that is segmented and "wrapped" with a smooth surface (e.g., tooth T3 is segmented and wrapped with surface S). Similarly, other portions of the intraoral surface scan model (gingiva, root, etc.) and / or volume scan model may be segmented and wrapped for display and / or analysis. In some variations, the model corresponding to the surface scan data and the model corresponding to the volume scan data may each be segmented and / or wrapped individually and separately. Alternatively, in some variations, as described below, segmentation and / or wrapping may alternatively be performed on an integrated patient model previously obtained by superimposing the surface scan data and the volume scan data.

[0045] In some variations, model segmentation can be performed with manual input. For example, similar to what is described above, a user can place a marker on the model through a user interface to specify one or more anatomical features for defining a segmentation boundary, such as a plane or other surface between two teeth, between a tooth and the gums, or between a crown and a root. Alternatively, a marker can be placed on the integrated patient model after the scan data is superimposed in the superposition process described below. Once the marker is placed, it can be adjusted by the user. In other variations, markers representing segmentation boundaries can be automatically suggested and placed by a software algorithm (and can be confirmed and / or adjusted based on manual user input). For example, the proposed segmentation boundary can be automatically defined based on color pixel data in the surface scan data and / or the superimposed integrated patient model. As an illustrative example, a threshold color channel intensity change between adjacent pixels in the surface scan data and / or the superimposed integrated patient model can indicate a transition between light-colored teeth and darker or pink gums.

[0046] In addition, in some embodiments, model segmentation may be automatically performed based at least in part on the voxel density of various voxels in the volume scan model (and / or the integrated patient model). Because different types of tissue have different radiopacity, different types of patient tissue will be represented by different voxel densities in the volume scan data. For example, bone has a relatively higher radiopacity than the gingiva, and therefore will be represented in the CBCT scan with a greater voxel density than the gingiva. As another example, enamel and root dentin have higher radiopacity than the surrounding alveolar bone, and will be represented in the volume scan data with a greater voxel density than the surrounding bone. Therefore, in some embodiments, different regions in the integrated patient model can be automatically identified by monitoring threshold changes in voxel density on adjacent voxels in the integrated patient model to assist in segmentation.

[0047] In some variations, partial or complete segmentation of both the surface scan model and the volume scan model may be performed prior to superimposing the models to form an integrated patient model. In some variations, partial or complete segmentation of the integrated patient model may be performed after superimposing the (at least partially) unsegmented surface scan model and volume scan model. In other variations, the surface scan model or the volume scan model may be segmented after their superposition based at least in part on alignment information derived from the integrated patient model. For example, a pre-segmented intraoral surface scan model may have data regarding tooth-to-tooth boundaries and / or tooth-to-gingival boundaries, and may be used to "seed" or otherwise inform the identification and segmentation of the aligned volume data of the interface between the tooth root and the bone. For example, the gingival margin of a tooth may be extrapolated toward the root apex of the tooth, because the density values ​​of the voxels around the tooth margin identified in the intraoral surface scan may seed the identification and growth of the associated root of the tooth along the root-to-bone boundary.

[0048] Overlay data

[0049] The superimposed intraoral surface scan data and volume scan data 130 are used to generate a highly accurate integrated patient model that includes useful information from the surface scan data and the volume scan data, such as root orientation, tooth volume, etc. For example, Fig. 9 An illustrative integrated patient model including an overlay of an aligned surface scan model and a volume scan model is depicted. In general, the scan data can be imported into a software application on a computing device for display in a user interface. Software instructions stored on a machine-readable storage medium (described in further detail below) can enable display and manipulation of intraoral surface scan data and volume scan data on a computing device.

[0050] In some variations, software instructions may enable the intraoral surface scan data to be registered with the volume scan data so that the two scan data sets are aligned. The registered intraoral surface scan data and volume scan data may share a common coordinate system so that the resulting integrated patient model can be manipulated within the common coordinate system. The registration of the scan data may include, for example, the alignment of one or more anatomical landmarks (e.g., visible crown features) and / or fiducials (e.g., radiopaque and optically visible markers in the patient's mouth and / or on the patient's dental features). In general, the digitized surface scan model and the volume scan model can be aligned by calculating a best fit alignment algorithm, which may, for example, provide six degrees of freedom in adjustment and scaling as needed. The best fit algorithm may be performed once for the upper teeth and once for the lower teeth, respectively.

[0051] One or both of the intraoral surface scan data and the volume scan data may be rescaleable and / or rotatable to better facilitate alignment and superposition of the scan data. For example, the software instructions may enable display of one or more handle icons associated with "grab points" on the scan data. Such handle icons may be manipulated using a user input device such as a mouse or touch screen (e.g., using a "click and drag" function) to rescale and / or rotate the scan data. In addition, the software instructions may enable isolation of selected portions of the intraoral surface scan data and / or the volume scan data via cropping or other similar image editing functions.

[0052] In some variations, the superposition of the intraoral surface scan data and the volume scan data may be performed manually. For example, user input may manipulate one or both of the scan data sets until the scan data are appropriately scaled and / or aligned. As another example, the user may select a minimum number of points per jaw in corresponding positions on the surface scan model and the volume scan model (e.g., three or more on each jaw of each model) as key points, and align the corresponding key point sets on the models so that they are superimposed on the integrated patient model. In some variations, the superposition of the intraoral surface scan data and the volume scan data may be performed automatically using appropriate machine vision techniques (e.g., edge detection, corner detection, etc.). In other variations, the superposition of the intraoral surface scan data and the volume scan data may be performed semi-automatically using both manual and algorithmic techniques. For example, a user may manually indicate corresponding locations on multiple scan data images using virtual markers (e.g., placed on significant malocclusions, placed at key points such as along interproximal margins, along various coronal contours or gingival borders, etc.), and software instructions may be executed to automatically scale the images and / or align corresponding virtual markers as needed to generate a superimposed scan data set (e.g., using a suitable computational best fit algorithm). The results of such automatic or semi-automatic operations may be further adjusted using manual input and / or require manual input to indicate approval of the automatically or semi-automatically generated integrated patient model.

[0053] After at least a portion of the intraoral surface scan data and at least a portion of the volume scan data are superimposed to generate an integrated patient model, the integrated patient model can be displayed in a user interface on a computing device for further use during diagnosis and / or treatment planning. For example, the integrated patient model can be rotated for viewing from different perspectives, displayed in a suitable cutaway or cross-sectional view.

[0054] In some variations, the intraoral surface scan data and the volumetric surface scan data may capture different states of the patient's dentition. For example, the intraoral surface scan and the volumetric scan may have been performed at different times, and the patient's structures (e.g., teeth, gums, etc.) may have moved during natural physiological processes (such as growth and remodeling) and / or through induced processes (such as orthodontic treatment). In these variations, such as if one or more teeth and / or jaws have moved, digital alignment of the surface scan model and the volumetric scan model may be performed on a tooth-by-tooth basis to help ensure accurate crown and root alignment between the models. In addition, in some variations it may be useful to segment the teeth of one of the two data sets (surface scan or volume scan) prior to superposition to help align the crowns with the roots.

[0055] Once registration or alignment of the surface scan model and the volume scan model is obtained, the crown morphology provided by any new (subsequent) surface scan can also be used to infer the new position of the root using the actual root morphology from the previous integrated patient model.

[0056] Determine the center of rotation

[0057] At least one tooth in the integrated patient model may be analyzed to determine its center of rotation (e.g., center of mass), which may be used in treatment planning to derive the natural axis of movement of the tooth, thereby advantageously reducing overall treatment time and improving treatment accuracy. In general, in some variations, a center of rotation may be determined for each tooth planned to be treated.

[0058] In some variations, the center of rotation of a tooth in an integrated patient model may be defined as a point located at a predetermined distance along the longitudinal axis of the tooth. In these variations, determining the center of rotation of the tooth may include determining the longitudinal axis of the tooth. The longitudinal axis of the tooth may be manually defined based on user input (e.g., by placing one or more marks on the integrated patient model for the tooth). For example, a user may visually inspect the tooth in at least one perspective view of the integrated patient model and mark or adjust a center line extending axially along the tooth (including the crown and the root). An exemplary method of manually identifying the longitudinal axis of a tooth includes: marking a first line that generally divides the tooth into two longitudinal halves of equal volume when viewed from a first side view perspective; and marking a second line that generally divides the tooth into two longitudinal halves of equal volume when viewed from a second side view perspective. The first line and the second line may extend into planes, and the longitudinal axis of the tooth may be defined as a line of intersection between the two planes. Another exemplary method of manually identifying the longitudinal axis of a tooth includes marking the top center point of the tooth when viewed from a top perspective, and marking the bottom center point of the tooth when viewed from a bottom perspective. In this example, the longitudinal axis of the tooth can be defined as a line extending between the top center point and the bottom center point of the tooth.

[0059] After determining the longitudinal axis of the tooth, the center of rotation of the tooth may be determined as a point located at a predetermined distance along the longitudinal axis. In some variations, for example, the center of rotation may be defined as a predetermined distance along the longitudinal axis of the tooth from the base of the root to the tip of the root. In an exemplary variation, the center of rotation may be determined as a point at about one-third of the length of the tooth measured along the longitudinal axis of the tooth from the base of the root to the tip of the root.

[0060] For example, Figure 3 As shown in the schematic diagram of FIG. 3 , the longitudinal axis L1 of the tooth 310 (as projected onto Figure 3 The center of rotation of tooth 310 (in a side view of tooth 310) can be determined to extend generally between the tip of the root of tooth 310 and the upper surface of the crown of tooth 310. The center of rotation of tooth 310 (indicated by the triangular mark) can be estimated to be located between about one-third and about one-half or about one-third of the length of the root of tooth 310 measured in the apical direction (toward the tip of the root) along longitudinal axis L1. In other words, the center of rotation is approximately located at a distance X from the base of the root and a distance 2X from the tip of the root. As another example, if Figure 3 As shown in the schematic diagram of FIG. 1 , the longitudinal axis L2 of the tooth 320 (as projected onto Figure 3The center of rotation of the tooth 320 (in the side view of the tooth 320) can be determined to extend generally between the bottom center point of the tooth 320 and the upper center point of the tooth 320. Generally, the center of rotation of the tooth 320 (indicated by the triangular mark) can be estimated to be located between about one-third and about one-half or about one-third of the length of the root of the tooth 320 measured in the apical direction (toward the tip of the root) along the longitudinal axis L2. In other words, the center of rotation is approximately located at a distance Y from the base of the root and a distance 2Y from the tip of the root.

[0061] In some variations, the center of rotation (center of mass) of the tooth may be automatically determined based on software structured analysis of the integrated patient model. For example, as described above, different anatomical regions (e.g., crown, root, periodontal ligament, bone, etc.) may be identified based on voxel density. Given such identification of these regions, the total volume and overall shape of the tooth (including the crown and root) may be automatically determined in the integrated patient model. Thus, the center of rotation may be automatically determined by analyzing the volume of the tooth as depicted in the integrated patient model.

[0062] In general, in some variations, the determined center of rotation may be the center of resistance of the root or portion thereof.The center of resistance may be defined as the point where a single force (whose line of action passes through the center of resistance) produces a translation of the tooth in the direction of the line of action of the applied force.

[0063] In one variation, the center of rotation of the tooth is determined based on the calculated center of resistance of the anatomical root of the tooth. Fig. 10A As shown, the anatomical root (AR) of the tooth extends from the crown to the root at the dentin enamel junction (DEJ) to the root apex. Voxel data of the anatomical root is provided by a volume scan of the patient (separately or in an integrated patient model). In these variations, the center of resistance of the tooth is between about 1 / 3 and about 1 / 2 of the distance from the DEJ to the root apex along the longitudinal axis of the anatomical root. This involves the calculation of the center of mass of the cone and the calculation of the center of mass of the cylinder, because the root morphology of the tooth tapers unevenly toward the tip (some are between cone and cylinder). Fig. 10B Determination of an exemplary center of resistance (C) based on the anatomical root extending from the DEJ along the longitudinal axis (LA) is shown.

[0064] In another variant, the center of rotation of the tooth is determined based on the calculated center of resistance of the functional root of the tooth. Fig.11A As shown in the schematic diagram of a healthy ("normal") tooth depicted in Figure , the functional root (FR) is the anatomical root of the tooth ( Fig. 10AThe functional root is defined as the smaller portion of the AR (in the anatomical root) that extends from the crestal bone height (CBH) to the root apex, or equivalently the length of the root surrounded by bone (some "non-functional" portions of the anatomical root may extend above the crest of the crest of the surrounding bone). The functional root may alternatively be defined as the volume of the root having the contact surface of the periodontal ligament in direct contact with the surrounding bone. In this variation, the center of resistance of the functional root is between about 1 / 3 and about 1 / 2 of the distance from the base of the functional root to the apex of the functional root. For example, Fig. 11B Determination of an exemplary center of resistance (C) based on a functional root along the longitudinal axis (LA) is shown. Specifically, the center of resistance (C) is located at approximately 1 / 3 of the distance along the longitudinal axis (LA) between the crestal bone height (CBH) shown in dashed lines and the root apex. Therefore, when forces are applied to the tooth during orthodontic treatment, the tooth is expected to move about the center of resistance (C). For example, Fig. 11C Projection view of a tooth tilted (crown tilted anteriorly, root tilted posteriorly) in predicted rotation about the center of resistance (C) due to forces applied to the tooth.

[0065] In some cases, the functional root may differ significantly in length from the anatomical root, such as for an unhealthy or abnormal tooth. Therefore, in some variations, it may be more accurate to use the functional root rather than the anatomical root to determine the center of resistance (as the center of rotation). For example, Fig. 12A is a schematic diagram of a tooth surrounded by crestal bone having a reduced height. Due to reduced crestal bone height (CBH) and gingival recession, there is a large portion of the anatomical root that is exposed (between the functional crown (FC) and the gingiva). Because the functional root is associated with the actual portion of the root that is constrained by the crestal bone, using the functional root to determine the center of rotation is more likely to represent the physical movement of the tooth than using the anatomical root's center of rotation to determine it. For example, Fig. 12B Determination of an exemplary center of resistance (C) based on a functional root along the longitudinal axis (LA) is shown. Specifically, the center of resistance (C) is located at approximately 1 / 3 of the distance along the longitudinal axis (LA) between the reduced crestal bone height (CBH) shown in dashed lines and the tip of the root. Therefore, when forces are applied to the tooth during orthodontic treatment, the tooth is expected to move about the center of resistance (C). For example, Fig. 12C A projection view of a tooth tilted (crown tilted forward, root tilted backward) in predicted rotation about the center of resistance (C) due to forces applied to the tooth is shown. Such predicted movement based on determination using a functional root is more likely to be more accurate than a similar predicted movement based on determination using an anatomical root.

[0066] In other variations, a user may manually select (e.g., place a marker or otherwise indicate) the center of rotation (e.g., based on visual inspection). Fig.13 As shown, the user can manually select the center of rotation of the tooth as a user-selected position, which can be located at a preferred distance from the root apex (or coincident with the root apex) along the longitudinal axis of the tooth.

[0067] The voxel density of the volumetric data of the bone surrounding the tooth can be greater or less because the reflection of the patient's bone is more or less dense. Therefore, the density of the voxel data of the surrounding bone can affect the magnitude and / or direction of the force required to move the tooth and / or can affect the limits of tooth movement within the alveolar bone or cortical bone of the patient's jaw. Therefore, the center of rotation of the tooth can be based at least in part on the voxel density corresponding to the bone surrounding the tooth.

[0068] Any of the above-described variations of determining the center of rotation of a tooth may be automatically performed or presented to a user (e.g., within a software application) as an option for selection. Furthermore, in some variations, two or more of the above-described variations of determining the center of rotation of a tooth may be performed, and their results may be averaged to generate an average center of rotation of the tooth. Additionally or alternatively, any one or more of the above-described variations of determining the center of rotation of a tooth may be performed, and the resulting position may be manually adjusted by a user (e.g., up or down along the longitudinal axis of the tooth), if desired.

[0069] Patient facial phenotype analysis

[0070] One variable that tends to affect the complexity of orthodontic treatment is the facial phenotype of the patient. There are two extreme phenotypes that differ from the normal phenotype in opposite ways: brachycephalic and doubly headed. These two phenotypes can be identified by the degree and direction of cranial (i.e., visceral) development. These qualities can be calculated directly and / or inferred from morphological features within the patient's volume scan data. These phenotypes affect the magnitude and direction of the forces applied to the teeth for tooth movement during orthodontic treatment and the design of the orthodontic device. For example, facial phenotype data can affect how the teeth must be moved in order to correct or mask differences from normal dental relationships. In other words, the same dental relationship may require different treatment if the patient is brachycephalic rather than doubly headed, and vice versa.

[0071] The skull of a brachycephalic individual is characterized by a shorter and broader face. Additional features typically include stronger jaw musculature, denser jawbones, increased bite forces, and characteristic occlusal relationships, such as a deep overbite. These individuals tend to have a low-diverging mandible that is angled differently relative to the skull than normal individuals. The dental consequences of this facial shape include increased complexity of orthodontic treatment, greater difficulty in treatment, and increased risk of wear between the upper and lower incisors. Therefore, in some variations, orthodontic treatment planning methods and systems, such as those described herein, may be used to provide more accurate and efficient orthodontic treatment for brachycephalic individuals.

[0072] The skull of a dolichocephalic individual is characterized by a longer, narrower face. Additional features include weaker jaw musculature, less dense bone, reduced bite forces, and characteristic bite relationships, such as an open bite. These individuals tend to have a highly divergent mandible that is angled differently relative to the skull than normal individuals. This facial shape may be associated with nasal airway obstruction during facial development. The dental consequences of this facial shape include increased complexity of orthodontic treatment, greater difficulty in treatment, and increased risk of wear between the upper and lower posterior teeth. Therefore, in some variations, orthodontic treatment planning methods and systems, such as those described herein, may be used to provide more accurate and efficient orthodontic treatment for dolichocephalic individuals.

[0073] Treatment plan

[0074] As described herein, utilizing an integrated patient model (as a combination of intraoral surface scan data and volume scan data) enables more accurate identification of the true center of rotation of the patient's teeth, thereby improving the accuracy of orthodontic treatment planning and reducing overall orthodontic treatment time compared to conventional treatment planning methods that use, for example, only intraoral surface scan data. For example, the longitudinal axis of a tooth can be determined based solely on intraoral surface scan data (e.g., identifying a longitudinal axis that roughly divides the surface appearance of the tooth in half in at least two planes), and the center of rotation along the longitudinal axis can be identified for treatment planning purposes. However, the intraoral surface scan data cannot capture changes in the crown and root morphology of the tooth. Therefore, such a longitudinal axis for the tooth (and the center of rotation determined based on the longitudinal axis) tends to be inaccurate, resulting in less effective treatment. In contrast, as described herein, the longitudinal axis of the tooth can be determined based on an integrated patient model that incorporates both intraoral surface scan data and volume scan data. Such a longitudinal axis for the tooth (and the center of rotation determined based on the longitudinal axis) tends to be more accurate, resulting in more effective and efficient treatment. Thus, in some variations, the methods described herein may comprise generating an appropriate treatment plan based at least in part on a determined center of rotation of one or more teeth.

[0075] In some variations, the treatment plan may include generating a series of one or more appliance trays having tooth receiving cavities, each appliance tray corresponding to a corresponding tooth arrangement, so that a patient who wears the series of appliance trays in a particular order (e.g., one tray every week, every two weeks, every three weeks, or other suitable time period) experiences a gradual transition of their dentition from the original tooth arrangement to the desired or targeted tooth arrangement. The form of the appliance trays may correspond to different stages of gradually moving each of one or more teeth around a corresponding rotation center determined as above. For example, each appliance tray may correspond to a corresponding tooth arrangement, so that the series of appliance trays gradually moves the teeth in a treatment path according to the rotation center of the teeth for natural movement. The appliance trays may be formed, for example, of a rigid or semi-rigid polymer (e.g., by vacuum forming, injection molding, 3D printing, etc.). The appliance trays may be provided to the patient individually (e.g., shipped one at a time according to predetermined intervals) or in one or more groups.

[0076] Fig.14 An exemplary model corresponding to intraoral surface scan data of a patient's dentition is depicted. The surface scan information is analyzed to determine a longitudinal axis (LA1) passing through the incisors (T). Fig.14 As shown, the treatment plan for the patient involves a 50 degree rotation of the incisors (T) about the longitudinal axis (LA1). However, as shown in the volume scan image depicting the patient's dentition Fig.15 As shown, the longitudinal axis (LA1) is substantially angularly offset from the general axis of the root (R) of the incisor (T), indicating that the determined longitudinal axis (LA1) is inaccurate or incorrect for the incisor (T).

[0077] In contrast, Fig.16 An exemplary partially integrated patient model with superimposed intraoral surface scan images and volume scan images of the patient's dentition is depicted. Specifically, Fig.16 A partially integrated patient model including a surface scan image of an incisor (T) and a portion of a volume scan image depicting a root (R) of the incisor (T) is depicted. The integrated patient model is analyzed to determine a longitudinal axis (LA2) passing through the incisor (T) and along the root (R). A center of rotation (center of resistance (C)) is selected at 1 / 3 of the distance along the longitudinal axis (LA2) from the reduced crest height to the tip of the root (similar to the above reference FIG. 12A to FIG. 12C described). Fig.17 A patient's treatment phase is depicted, which involves a 50 degree rotation of the incisors (T) about the longitudinal axis (LA2).

[0078] Because the longitudinal axis (and center of rotation) for the incisor (T) is at the same Fig.14 (intraoral surface scan only) and Fig.16The treatment planning approach associated with the incisors (T) is different because the rotation paths of the incisors (T) about these different axes and centers of rotation are also different. Fig.18A Depicted Fig.14 and Fig.17 , and illustrates the relative inaccuracy of the longitudinal axis (LA1) compared to the longitudinal axis (LA2). Fig.18B The significant errors in the longitudinal axis (LA1) based only on the intraoral surface scan data (which are associated with the errors in the determined center of rotation) are summarized. Fig.18B As shown in the table, using only the intraoral surface scan results in determining the longitudinal axis (LA1) with a labiolingual tilt error of approximately 12.42 degrees, a mesiodistal angulation error of approximately 11.56 degrees, and a rotation error of approximately 47.29 degrees. In addition, using only the intraoral surface scan results in determining the longitudinal axis (LA1) with a translation error measured from the rotation center in LA2 as a starting point, including a left / right error of approximately 2.95 mm, a forward / backward error of approximately 3.17 mm, and an extension / depression error of approximately 0.64 mm.

[0079] Systems for orthodontic treatment planning

[0080] Figure 2 Various components of an exemplary system for orthodontic treatment planning are shown. Specifically, the exemplary system may include a general computing device 230, which includes one or more processors 240, one or more storage devices 250, one or more network communication devices 260, one or more output devices 270, and / or one or more user interfaces 280. Exemplary general computing devices include desktop computers, laptop computers, and mobile computing devices (e.g., tablet computers, mobile phones).

[0081] The processor 240 may be any suitable processing device configured to run and / or execute an instruction set or code, and may include one or more data processors, image processors, graphics processing units, physical processing units, digital signal processors, and / or central processing units. The processor may be, for example, a general purpose processor, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), etc. The processor may be configured to run and / or execute application processes and / or other modules, processes, and / or functions associated with the system and / or a network associated with the system. The following device technologies may be provided in various component types (e.g., MOSFET technology, such as complementary metal oxide semiconductor (CMOS); bipolar technology, such as emitter coupled logic (ECL); polymer technology (e.g., silicon conjugated polymer and metal conjugated polymer-metal structure); mixed analog and digital, etc.).

[0082] In some variations, the memory 250 may include a database and may be, for example, a random access memory (RAM), a memory buffer, a hard drive, an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), a read-only memory (ROM), flash memory, etc. The memory may store instructions to cause the processor to execute modules, processes, and / or functions, such as scan data processing and alignment. In some variations, the memory 250 may receive the intraoral surface scan data 212 and / or the volume scan data 222 in its entirety (e.g., a DICOM file generated by scanner-specific software). Additionally or alternatively, the memory 250 may receive the intraoral surface scan data 212 and / or the volume scan data 222 in part, such as directly feeding the data in real time or near real time from the intraoral scanner 210 and / or the volume scanner 220.

[0083] Some variations described herein relate to computer storage products with non-transitory computer-readable media (also referred to as non-transitory processor-readable media) having instructions or computer code for performing various computer-implemented operations thereon. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it does not include transitory propagating signals per se (e.g., propagating electromagnetic waves that convey information over a transmission medium such as space or a cable). The medium and computer code (also referred to as code or algorithm) may be those designed and constructed for a specific purpose.

[0084] Examples of non-transitory computer-readable media include, but are not limited to: magnetic storage media, such as hard disks, floppy disks, and magnetic tapes; optical storage media, such as compact disks / digital video disks (CD / DVD); compact disk read-only memories (CDROMs) and holographic devices; magneto-optical storage media, such as optical disks; solid-state storage devices, such as solid-state drives (SSDs) and solid-state hybrid drives (SSHDs); carrier signal processing modules; and hardware devices that are specifically configured to store and execute program code, such as application specific integrated circuits (ASICs), programmable logic devices (PLDs), read-only memories (ROMs), and random access memory (RAM) devices. Other variations described herein relate to computer program products that may include, for example, instructions and / or computer code disclosed herein.

[0085] The systems, devices and / or methods described herein may be implemented by software (implemented on hardware), hardware, or a combination thereof. Hardware modules may include, for example, a general purpose processor (or microprocessor or microcontroller), a field programmable gate array (FPGA), and / or an application specific integrated circuit (ASIC). Software modules (implemented on hardware) may be expressed in a variety of software languages ​​(e.g., computer code), including C, C++, Python, Ruby, Visual and / or other object-oriented procedural languages ​​or other programming languages ​​and development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions (such as generated by a compiler), code for generating network services, and files containing high-level instructions executed by a computer using an interpreter. Other examples of computer code include, but are not limited to, control signals, encrypted code, and compressed code.

[0086] In addition, one or more network communication devices 260 may be configured to connect the general computing device to another system (e.g., the intraoral scanner 210, the volumetric scanner 220, the Internet, a remote server, a database, etc.) via a wired or wireless connection. In some variations, the general computing device may communicate with one or more other general computing devices via one or more wired or wireless networks. In some variations, the communication device may include a radio frequency receiver, transmitter, and / or an optical (e.g., infrared) receiver and transmitter that is configured to communicate with one or more devices and / or networks. In an exemplary variation, the network communication device 260 may include a cellular modem (e.g., a 3G / 4G cellular modem) such that it advantageously does not rely on Internet Wireless Fidelity (WiFi) access to connect.

[0087] Alternatively, the wireless communication may use any of a variety of communication standards, protocols, and technologies, including, but not limited to, Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), High Speed ​​Downlink Packet Access (HSDPA), High Speed ​​Uplink Packet Access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, Dual-Cell HSPA (DC-HSPDA), Long Term Evolution (LTE), Near Field Communication (NFC), Wideband Code Division Multiple Access (W-CDMA), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Bluetooth, WiFi, Voice over Internet Protocol (VoIP), or any other suitable communication protocol. In some variations, the devices herein may communicate directly with each other without transmitting data over a network (e.g., via NFC, Bluetooth, WiFi, RFID, etc.). For example, devices (e.g., one or more computing devices, intraoral scanner 210 and / or volumetric scanner 220, etc.) may communicate directly with each other in a paired connection (a 1:1 relationship) or in a star connection or broadcast connection (a "one-to-many" or 1:m relationship). As another example, devices (e.g., one or more computing devices and / or intraoral scanner 210 and / or volumetric scanner 220, etc.) can communicate with each other via a mesh networking connection (e.g., a "many-to-many" or m:m relationship) (such as via Bluetooth mesh networking).

[0088] As described above, a computing device in the system may include one or more output devices 270, such as a display and / or an audio device for interfacing with a user. For example, the output device may include a display that allows a user to view an integrated patient model, treatment plan steps, and / or other appropriate information related to the diagnosis and / or treatment plan for orthodontic treatment. In some variations, the output device may include a display device that includes at least one of the following: a light emitting diode (LED), a liquid crystal display (LCD), an electroluminescent display (ELD), a plasma display panel (PDP), a thin film transistor (TFT), an organic light emitting diode (OLED), an electronic paper / electronic ink display, a laser display, and / or a holographic display. In some variations, the audio device may include at least one of the following: a speaker, a piezoelectric audio device, a magnetostrictive speaker, and / or a digital speaker.

[0089] The computing device may also include one or more user interfaces 280. In some variations, the user interface may include an input device (e.g., a touch screen) and an output device (e.g., a display device), and is configured to receive input data. The input data may include, for example, selection of image scan data (e.g., for rotation, cross-sectional viewing, segmentation, and / or other suitable manipulations), selection or placement of markers (e.g., to facilitate registration of surface scan data and volume scan data and / or facilitate model segmentation as described above), and / or other interactions with the user interface. For example, user control of an input device (e.g., a keyboard, a button, a touch screen) may be received by the user interface and then may be processed by the processor and the memory. Some variations of the input device may include at least one switch configured to generate a control signal. For example, the input device may include a touch surface for a user to provide input corresponding to a control signal (e.g., a finger contacts the touch surface). An input device including a touch surface may be configured to detect contact and movement on the touch surface using any of a variety of touch-sensitive technologies, including capacitive technology, resistive technology, infrared technology, optical imaging technology, scattered signal technology, acoustic pulse recognition technology, and surface acoustic wave technology. In variations of the input device including at least one switch, the switch may include, for example, at least one of a button (e.g., hard key, soft key), a touch surface, a keyboard, an analog stick (e.g., a joystick), a directional pad, a mouse, a trackball, a jog switch, a step switch, a rocker switch, a pointer device (e.g., a stylus), a motion sensor, an image sensor, and a microphone. The motion sensor may receive user movement data from an optical sensor and classify user gestures as control signals. The microphone may receive audio data and recognize user voice as a control signal.

[0090] For the purpose of explanation, the foregoing description uses specific nomenclature to help a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that specific details are not required to practice the present invention. Therefore, the foregoing description of specific embodiments of the present invention is presented for the purpose of illustration and description. These specific embodiments are not intended to be exhaustive or to limit the present invention to the precise form disclosed; obviously, in view of the above teachings, many modifications and variations are possible. The embodiments are selected and described in order to explain the principles of the present invention and its practical application, so that other persons skilled in the art can utilize the present invention and various embodiments with various modifications suitable for the specific purpose envisioned. The following claims and their equivalents are intended to define the scope of the present invention.

Claims

1. A system for performing orthodontic treatment planning for a patient, the system comprising: at least one memory device configured to receive and store three-dimensional intraoral surface scan data of the patient's dentition and three-dimensional volume scan data of the dentition; as well as at least one processor configured to: superimposing the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis; determining a volume of the at least one tooth, and determining the longitudinal axis of the at least one tooth in the integrated patient model based on the determined volume; as well as For use in planning orthodontic treatment, a center of rotation of the at least one tooth is determined, wherein the center of rotation is defined as a point in the integrated patient model located at a predetermined distance from the base of the root to the tip of the root along the longitudinal axis of the at least one tooth.

2. The system of claim 1 , wherein the at least one processor is configured to determine the center of rotation of the at least one tooth by automatically determining a volume of the at least one tooth, and determining the longitudinal axis of the at least one tooth in the integrated patient model based on the determined volume.

3. The system of claim 1, wherein the at least one processor is configured to determine the longitudinal axis of the at least one tooth in the integrated patient model by dividing the determined volume of the at least one tooth into two longitudinal halves of equal volume.

4. The system of claim 1, wherein the determined center of rotation of the at least one tooth is defined as a point along the longitudinal axis that is between one third and one half of the distance from the base of the root to the tip of the root.

5. The system of claim 4, wherein the root is an anatomical root of the at least one tooth.

6. The system of claim 4, wherein the root is a functional root of the at least one tooth.

7. The system of claim 1, wherein the at least one processor is configured to determine the center of rotation of the at least one tooth by determining a center of resistance of the root of the at least one tooth.

8. The system of claim 7, wherein the root is an anatomical root of the at least one tooth.

9. The system of claim 7, wherein the root is a functional root of the at least one tooth.

10. The system of claim 1, wherein the intraoral surface scan data comprises optical color scan data.

11. The system of claim 1 , wherein the volume scan data comprises CBCT X-ray scan data.

12. The system of claim 1, wherein the at least one processor is configured to superimpose the intra-oral surface scan data and the volume scan data by registering the intra-oral surface scan data with the volume scan data.

13. The system of claim 1, the at least one processor configured to automatically separate the root of the at least one tooth from a portion of the integrated patient model surrounding the root.

14. The system of claim 13, wherein the at least one processor is configured to automatically separate the root of the at least one tooth, the periodontal ligament associated with the at least one tooth, and the bone surrounding the at least one tooth in the integrated patient model based at least in part on voxel density.

15. The system of claim 14, wherein the at least one processor is configured to automatically separate the root of the at least one tooth by determining the voxel density of the at least one tooth in the integrated patient model, and comparing the determined voxel density to a predetermined threshold voxel density for the at least one tooth.

16. The system of claim 14, wherein the at least one processor is configured to automatically separate the root of the at least one tooth by: determining a first voxel density of the at least one tooth in the integrated patient model; determining a second voxel density of at least one of: one or more periodontal ligaments associated with the at least one tooth in the integrated patient model, and bone surrounding the at least one tooth in the integrated patient model; And comparing a difference between the first voxel density and the second voxel density to a predetermined threshold difference.

17. The system of claim 1, wherein the orthodontic treatment comprises: A plurality of appliance trays having tooth receiving cavities are generated, each appliance tray corresponding to a respective tooth arrangement.

18. The system of claim 1, further comprising: a display configured to display the integrated patient model; and a user interface for navigating the integrated patient model.

19. A system for performing orthodontic treatment planning for a patient, the system comprising: at least one memory device configured to receive and store three-dimensional intraoral surface scan data of the patient's dentition and three-dimensional volume scan data of the patient's dentition and craniofacial structure; as well as at least one processor configured to: superimposing the intraoral surface scan data and the volume scan data to generate an integrated patient model including a root of at least one tooth having a longitudinal axis; automatically separating the root of the at least one tooth from a portion of the integrated patient model surrounding the root; as well as For use in planning orthodontic treatment, a center of rotation of the at least one tooth is determined based at least in part on a voxel density in the root of the at least one tooth relative to a voxel density in a portion of the integrated patient model surrounding the root.

20. The system of claim 19, wherein the processor is configured to automatically separate the root of the at least one tooth, a periodontal ligament associated with the at least one tooth, and a bone surrounding the at least one tooth in the integrated patient model based at least in part on voxel density.

21. The system of claim 20, wherein the processor is configured to automatically determine a volume of the at least one tooth and to determine the longitudinal axis of the at least one tooth in the integrated patient model.

22. The system of claim 19, wherein the intraoral surface scan data comprises optical color scan data.

23. The system of claim 19, wherein the volume scan data comprises CBCT X-ray scan data.

24. The system of claim 19, wherein the processor is configured to register the intra-oral surface scan data and the volume scan data when superimposing the intra-oral surface scan data and the volume scan data.

25. The system of claim 19, wherein the orthodontic treatment comprises: A plurality of appliance trays having tooth receiving cavities are generated, each appliance tray corresponding to a respective tooth arrangement.

26. The system of claim 19, further comprising: a display configured to display the integrated patient model; and a user interface for navigating the integrated patient model.

Images