Method for semi-automatically determining virtual dentition occlusion

Abstract

An aspect of the present disclosure provides a method of determining a virtual bite. The method may include obtaining a three-dimensional representation of a first jaw part and a second jaw part of a patient. The method may further include representing, in a GUI, an initial position of the first jaw part relative to the second jaw part using the three-dimensional representation, the initial position being defined by six predetermined degrees of freedom relative to a coordinate system fixed relative to the first jaw part. The method may further include receiving a user input of a change to at least one of the degrees of freedom and automatically adjusting at least one of the other degrees of freedom to minimize a perpendicular distance of a control point relative to an origin, thereby determining the virtual bite. The method may further include representing, in the GUI, the first jaw part and the second jaw part into the determined virtual bite.

Description

Detailed Description of the Invention

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to International Application No. PCT / US2022 / 046533, filed October 13, 2022, which claims the benefit of and priority to U.S. Provisional Application No. 63 / 266,079, filed December 28, 2021, both of which are incorporated by reference in their entireties and for all applicable purposes as if fully set forth below.

[0002] [Technical field] Aspects of the present disclosure relate to determining occlusion. In some aspects, the present disclosure relates to an apparatus, system, and method for determining a virtual occlusion for orthognathic surgery planning, among other things.

[0003] Related Art In orthognathic surgery, surgeons perform osteotomies to reposition the teeth in one or both jaws with the goal of alleviating clinical and aesthetic problems caused by severe jaw misalignment that cannot be treated by orthodontics alone. Computer-aided planning systems (such as Materialise's®, ProPlan CMF, SurgiCase®, Mimics®, etc.) assist surgeons in predicting the functional and aesthetic outcomes of the procedure. Such planning systems can provide 3-D printed dental splints for use during surgery to guide the teeth toward the planned positions. The user of such software systems must specify the relative positions and orientations of the teeth, or parts thereof, of both jaws (i.e., the upper jaw relative to the lower jaw, or vice versa) when the patient brings the jaws together to bite. The relative positions and orientations of the teeth of both jaws when the patient brings the jaws together to bite are referred to as the patient's occlusion.

[0004] In some orthognathic cases, the surgeon may need to make additional osteotomies to divide the maxilla and / or mandible into multiple segments. Each segment is then repositioned slightly differently. This is called a mandibular or maxillary split. For example, the maxilla or mandible may be too small to maintain proper occlusion, or may be necessary to achieve an acceptable functional or aesthetic outcome for the patient. Typically, segments of one jaw are repositioned slightly further apart than they were before surgery. In such cases, occlusion includes the relative position and orientation of all jaw segments with respect to the other jaw. If the planned intervention involves splitting both the maxilla and mandible, occlusion includes the relative position and orientation of all jaw segments with respect to one arbitrarily selected segment in one of the jaws.

[0005] In some orthognathic cases, the surgeon may decide to remove material from the biting surface of one or more teeth by grinding or burring during or after orthognathic surgery. For example, parts of one or more teeth may protrude beyond the other teeth in the same jaw, preventing proper occlusion. In such cases, burring the protruding portions of the teeth may allow the teeth in both jaws to contact at different points, improving the patient's postoperative occlusion.

[0006] The occlusion is determined by optical scanning of dental cast models that are physically placed in occlusion by the surgeon. Figure 1 shows a conventional workflow for identifying occlusion for computer-aided orthognathic surgery planning. In step 2 of Figure 1, impression molds are made of the patient's upper and lower jaws. In step 4, a plaster model is made from the impression molds. In step 6, the two plaster models are placed in an articulator to determine and represent the desired occlusion. In step 8, the plaster model is fixed in the desired occlusion. In step 10, the fixed plaster model is optically scanned and used in the computer-aided planning system.

[0007] In the case of a maxillary split or mandibular split, step 4 of FIG. 1 further involves physically cutting one or both plaster casts to simulate the additional osteotomies that will be made to split the corresponding jaw. The resulting pieces of each cast are then fixed together in different relative positions and orientations to represent the desired new shape of the split jaw.

[0008] However, in many cases, such an "occlusion scan" may not be readily available. For example, surgeons may prefer a fully digital workflow that uses intraoral scans of the teeth instead of casts. As another example, the relative position of the casts (representing the desired occlusion) may be disturbed prior to the optical scan, e.g. during transport.

[0009] In such cases, the surgeon must specify the occlusion by other means, such as manually rotating and translating three-dimensional models of the jaws and / or jaw parts relative to one another using a user interface integrated into the planning software until the desired occlusion is obtained. FIG. 2 shows an example of an all-virtual workflow for specifying an occlusion for computer-aided planning of orthognathic surgery. At step 22A, a plaster model (created as described above in connection with steps 2 and 4 of FIG. 1) is optically scanned. Alternatively, at step 22B, both jaws are optically scanned intraoral. At step 24, the optical scan is provided to the planning software, and a user of the planning software (e.g., the surgeon) manipulates the user interface to determine the desired occlusion. At step 26, the planning software depicts the jaws in the desired occlusion for surgical planning. The depiction of the desired occlusion by the planning software is referred to herein as a virtual occlusion.

[0010] In cases where the mandible or maxilla is split, the complete specification of occlusion requires determining the relative position and orientation of all jaw segments with respect to the other jaw segment. Thus, the user of the planning software must manually rotate and translate the 3D models of all jaw segments except one. This is the same process used to specify occlusion for unsplit jaws and may be repeated multiple times.

[0011] As will be appreciated, occlusion is defined by the position and rotation of the moving jaws relative to a coordinate system whose origin is fixed relative to the fixed jaws. With reference to FIG. 3 and as described herein, the coordinate system of the moving jaw portion 100 is referred to as a local coordinate system (LCS) 102 having orthogonal X', Y', and Z' axes. The coordinate system of the fixed jaw portion 104 is referred to as a world coordinate system (WCS) 106 having orthogonal X, Y, and Z axes. Occlusion 108 can be mathematically defined by the location of the origin and axis orientation of the LCS 102 attached to the moving jaw portion 100 as defined by the WCS 106.

[0012] In this manner, the position of the moving jaw portion 100 can be specified in terms of X, Y and Z coordinates in the WCS 106. Additionally, the orientation of the moving jaw portion 100 can be specified in terms of degrees of rotation about the X, Y and Z axes in the WCS 106. Thus, occlusion 108 is the position and orientation of the moving jaw portion 100 defined in six degrees of freedom (three positional degrees of freedom and three rotational degrees of freedom) relative to the WCS 106.

[0013] The definition of the coordinate system is arbitrary, i.e., as discussed herein and shown in Figure 3, the lower jaw may be defined as the moving jaw portion 100 to which the LCS 102 is attached and the upper jaw may be defined as the fixed jaw portion 104 to which the WCS 106 is attached. Alternatively, the lower jaw may be the fixed jaw portion 104 to which the WCS 106 is attached and the upper jaw may be the moving jaw portion 100 to which the LCS 102 is attached.

[0014] In the case of a split lower jaw or split upper jaw, as shown in FIG. 9, the unsplit jaw 104 can be considered as a fixed jaw part with attached WCSs 1061, 1062, 1063, and each split jaw part 1001, 1002, 1003 can be considered as a separate moving jaw part with its own LCS 1021, 1022, 1023. If only one jaw is split, the occlusion can be fully specified by defining the LCSs of all parts of that jaw. If both the upper and lower jaws are split, the occlusion can be defined iteratively. For example, first the lower jaw parts can be merged into one object and considered as a fixed jaw part, while the upper jaw parts can each be considered as separate moving jaw parts with their own LCS that can be moved and rotated individually. The upper jaw parts can then be merged and considered as fixed jaw parts. This has the effect of fixing the relative position and orientation of the upper jaw parts, and the lower jaw parts can be considered as separate moving jaw parts that can be manipulated individually. This process can be repeated, possibly under the control of a user of the planning software, or the iterative process can begin by merging the upper jaw segments into one fixed jaw segment while moving individual segments of the lower jaw, or the order of manipulating the lower and upper jaw segments can be reversed.

[0015] While the origin and orientation of the WCS 106 and LCS 102 may be defined arbitrarily, it may be convenient to define the XY plane of the WCS 106 as a plane tangential to the tooth surfaces of the fixed jaw portion 104. Similarly, it may be convenient to define the Z axis of the WCS 106 as orthogonal to the XY plane passing through the tooth midline of the fixed jaw portion 104. Similarly, it may be convenient to define the X'-Y' plane of the LCS 102 as a plane tangential to the tooth surfaces of the moving jaw portion 100. Similarly, it may be convenient to define the Z' axis of the LCS 102 as orthogonal to the X'-Y' plane passing through the tooth midline of the moving jaw portion 100.

[0016] In the case of a mandibular split or a maxillary split, one or more of the segments of the split jaw may consist of several adjacent teeth forming an approximately linear row, so that the segment has a very elongated shape. In such cases, it may be convenient to define the X'-Y' plane of the corresponding LCS as the tangent plane of the tooth surfaces of the split jaw. Furthermore, it may be convenient to align either the X' or Y' axis of the LCS so that it is parallel to the direction of the dentition that it represents. This corresponds to aligning the X' or Y' axis, respectively, with the tangent direction of the dentition arc. As a result, the Y' or X' axis, respectively, is perpendicular to the dentition arc and the direction of the dentition. Similarly, it may be convenient to define the Z' axis of the LCS as orthogonal to the X'-Y' plane and passing through the middle of the jaw (e.g. defined as the center of gravity). It may also be convenient to define the WCS for the opposite fixed jaw part in a coincident manner, with the X or Y axis tangent to the dentition arc, the Y or X axis orthogonal to the dentition arc, the XY plane tangent to the fixed jaw tooth surface, and the Z axis passing through the center (initial position) of the split part represented by the moving jaw part. Comparing such nearly coincident coordinate systems for the fixed jaw (part) and the moving jaw (part) makes it easier for the user to interpret the translation and rotation values. Figure 9 shows an example of the case of a split maxilla, where the teeth of the mandible 104 represent one jaw part and the teeth of the maxilla are split into three parts 1001, 1002 and 1003. In this example, the mandible is a fixed jaw part and each maxilla part is a separate moving jaw part. A separate LCS 1021, 1022, 1023 is defined for each maxillary part, including an origin indicated by a dot and three axes X'1, Y'1, Z'1; X'2, Y'2, Z'2; X'3, Y'3, Z'3. Axes X'1, X'2, X'3 are tangents (dashed lines) to the dentition arc. Axes Y'1, Y'2, Y'3 are perpendicular to the dentition arc and parallel to a horizontal plane tangent to the tooth surfaces. Axes Z'1, Z'2, and Z'3 are perpendicular to said horizontal plane. To determine the occlusion of a particular maxillary part, a corresponding WCS is defined, attached to the mandible 104. Different WCSs 1061, 1062, 1063 are shown for each maxillary part.The axes of the WCS are labelled X1, Y1, Z1 for the right part, X2, Y2, Z2 for the middle part and X3, Y3, Z3 for the left part. The definition of the WCS is similar to that of the LCS, with axes X1, X2, X3 tangent to the dentition arc (dashed line), axes Y1, Y2, Y3 parallel to a horizontal plane perpendicular to the dentition arc and tangent to the tooth surfaces, and axes Z1, Z2, Z3 perpendicular to said horizontal plane.

[0017] One possible orthognathic surgical planning tool, e.g., surgical planning software, may give the user complete control over the position and orientation of one of the jaw portions 100 and 104. That is, the user controls the position of the moving jaw portion 100 in all three spatial dimensions, as well as the rotation of the moving jaw portion 100 about all three major axes. While this gives the user complete control, it can be cumbersome to use due to the many factors that must be considered when determining the occlusion 108.

[0018] Specifically, to obtain a clinically stable occlusion 108, the teeth of both jaw portions 100, 104 must be in contact at least three points, where contact can be defined as a small overlap (point of intersection) of the three-dimensional models representing both sets of teeth, e.g., an overlap distance of about 0.3 mm (the exact value may vary depending on the surgeon or case). The contact points must be spaced far enough apart to obtain a stable occlusion 108. This can be verified by inspecting cross sections through the three-dimensional models of the teeth. To cover the entire surface of all teeth, a large number of these cross sections must be checked, a tedious process requiring significant time and / or processing resources.

[0019] Furthermore, the user must consider additional clinical requirements and trade-offs. For example, the dental midlines of both jaw portions 100, 104 must be aligned for aesthetic reasons. Furthermore, the anterior-posterior alignment of both jaw portions 100 and 104 must be set according to the surgeon's expectations. Changes that the user makes to the relative positions and orientations of the jaws in the user interface tend to simultaneously affect many of these often conflicting requirements. Thus, after each change, the user must verify whether such requirements have been met within acceptable limits.

[0020] In split mandible and split maxilla cases, the surgical planning software can give the user full control over the position and orientation of all segments of the split jaw, applied individually to each segment, using methods similar to those used when the jaw is not split, but this doubles the effort for the user, as the position and orientation manipulations must be performed separately for each segment.

[0021] The limitations of such potential solutions, and Pongracz, F., & Bardosi, Z. (2006), “Dentition planning with image-based occlusion analysis,” International Journal of Computer Assisted Radiology and Surgery, 1 (3), 149-156; Nadjmi, N., Mollemans, W., Daelemans, A., Van Hemelen, G., Schutyser, F., and Berge, S. (2010), “Virtual occlusion in planning orthognathic surgical procedures” International Journal of Oral and Maxillofacial Surgery 39, 457-462; and Deng, H., Yuan, P., Wong, S., Gateno, J., Garrett, FA, Ellis, RK, English, JD, Jacob, HB, Kim, D., Barber, JC, et al. (2020), “An automated approach to establish Due to limitations of previous solutions, such as those described in “clinically desired final dental occlusion for one-piece maxillary orthognathic surgery,” International Journal of Computer Assisted Radiology and Surgery 15(11):1763-1773, determining the virtual occlusion 108 using such solutions may only be performed by an expert clinical technician and not the surgeon himself. Furthermore, significant training may be required. Furthermore, determining the desired virtual occlusion 108 is a time-consuming process even for an experienced technician. For example, a difficult case may take from 15 minutes to an hour depending on the user's experience level.This may not allow the user to immediately make changes to the planned occlusion 108 when the surgeon requests such changes, further complicating the planning process.

[0022] On the other hand, other possible planning platforms may offer a fully automated approach, where the virtual occlusion 108 is proposed and set by an algorithm, leaving the user with little freedom to fine-tune the occlusion 108. This may result in suboptimal results that do not take into account factors that potentially only the surgeon can take into account, such as, for example, the surgical approach, pre- and post-operative soft tissue characteristics, aesthetic requirements, or outcome expectations.

[0023] It should be noted that the information contained in the "Background" section of this specification is intended merely to provide a reference for the discussion of particular embodiments herein. Description: No information contained in this Background should be construed as an admission of prior art. [Summary of Disclosed Embodiments]

[0024] In certain embodiments, based on the novel and inventive techniques described herein, the system uses a semi-automatic algorithm to simulate contacts between teeth of both jaws or parts thereof (jaw portions). A graphical user interface (GUI) allows a user to partially specify the relative positions and orientations of the jaws or parts thereof (jaw portions) using a limited set of clinically relevant spatial and rotational parameters. Changes made by the user to these parameters are received by the algorithm. The algorithm then adjusts a different limited set of spatial and rotational parameters to satisfy certain optimization constraints, leading to an occlusion 108 that is presented to the user in the GUI.

[0025] 4 (and the defined coordinate system of FIG. 3), aspects of the disclosure allow for user manipulation of the moving jaw portion 100, particularly with respect to three position variables relative to the WCS 106. For example, the user controls the translation of the moving jaw portion 100 in the X and Y directions, i.e., in the horizontal (XY) plane. The user also controls the rotation of the moving jaw portion 100 about the vertical (Z) axis. The user can also set the position of a control point 110. The control point 110 represents the pressure application point of the moving jaw portion 100.

[0026] In the case of a split mandible or split maxillary jaw, the moving jaw portion can represent either a portion of the jaw that results from splitting that jaw into multiple portions, or a portion of the jaw that combines some or all of the jaw portions into a single object. A user can switch between both representations to alternately manipulate the position and orientation of individual jaw portions, groups of jaw portions, or the entire jaw.

[0027] Based on user inputs that control the translational and rotational movements of the moving jaw portion 100 in the XY plane and set the control points, the algorithm applies certain optimization parameters (described in detail below) and calculates the vertical, i.e., vertical (Z) translation. The algorithm also calculates rotations about two horizontal (X and Y) axes to bring the teeth into optimized contact without modifying the parameters set by the user. Aspects of the present disclosure provide for division of labor; that is, the algorithm automatically performs the tedious task of ensuring that the teeth are in accurate contact, while the user operates a more limited, yet clinically relevant, set of parameters. This saves time and allows for more focus on the clinical aspects of the occlusion 108 during the planning process. Furthermore, collaboration between the surgeon using the planning software and the clinical engineer is simplified, since the parameters controlled by the user are defined to be equivalent to well-known clinical measurements used to describe the occlusion 108, such as overjet and midline deviation.

[0028] Mathematically (and as described above), occlusion 108 can be expressed as six degrees of freedom (DOF) of the moving jaw member 100 relative to the WCS 106 of the fixed jaw member 104. Thus, six separate values ​​together uniquely determine the position and orientation of the jaw members 100 and 104 relative to each other.

[0029] As mentioned above, either the upper or lower jaw can be defined as the moving jaw portion 100, while the other jaw remains fixed and will be referred to as the fixed jaw portion 104. As shown in Figure 3, the moving jaw portion 100 is represented in a local coordinate system (LCS) 102 that includes a point in three-dimensional space that serves as the origin, and three orthonormal three-dimensional vectors that represent the directions of the X', Y', and Z' axes of the LCS. The three spatial coordinates relative to the origin are the translational degrees of freedom. The axes of the LCS are completely determined by a system of three Euler (Cardan) angles, which are the rotational degrees of freedom.

[0030] In the case of mandible split or maxilla split, to allow the user to manipulate the position and orientation of the individual parts of the split jaw, the resulting part of either the maxilla or mandible split can be defined as the moving jaw part, while all parts of the other jaw remain fixed and are called the fixed jaw part.

[0031] To resolve ambiguity, an order of rotations may be specified. In certain embodiments, a ZXY order of rotations is applied. However, another order of rotations may be applied instead. Similarly, to resolve ambiguity, one may specify whether the rotations are intrinsic rotations (the axes are tied to the object that rotates) or extrinsic rotations (the axes remain stationary and the object rotates). In certain embodiments, an intrinsic rotation is applied. However, an extrinsic rotation may be applied instead.

[0032] The LCS 102 is defined relative to a world coordinate system (WCS) 106 on the fixed jaw part 104, and this coordinate system does not change. In the example described herein, for the LCS 102 and WCS 106 of each jaw 100, 104, the X-axis points left, the Y-axis points back, the Z-axis points up, and the origin is located between the two central incisors. The orientation of the WCS and LCS axes, as well as the order of rotation in the Euler angle system, are arbitrary choices, and the choices used here are not essential to the functionality of the embodiments discussed herein. However, it is convenient to define the WCS and LCS as being substantially parallel to each other when the fixed jaw part and the moving jaw part are in a relative position and orientation that can be considered neutral, for example, in a planned pre-operative relative position and orientation, as observed in pre-operative medical imaging. In typical use cases, the values ​​of rotation angles are low, so the choice of the sequence of Euler angles (XYZ, YXZ, etc.) and the choice between intrinsic and extrinsic rotations may not be noticeable to the user. In the following, rotations are expressed around the X, Y, and Z axes, but one skilled in the art will readily understand that rotations may be similarly defined around the X', Y', and Z' axes, respectively. The naming conventions and definitions of the coordinate system axes are not intended to limit the methods and systems disclosed herein. For example, a method or system described herein having axes defined as X-pointing left, Y-pointing backward, and Z-pointing up is fully equivalent to a method or system having axes defined as X-pointing right, Y-pointing forward, and Z-pointing up, or a method or system having axes defined as X-pointing forward, Y-pointing up, and Z-pointing right. Nevertheless, an unambiguous, preferably clinically appropriate definition can be selected.

[0033] Rotations may be defined around the WCS origin or around the LCS origin; however, choosing the LCS origin as the center of rotation may result in a more intuitive user experience. In the former case (rotations are defined around the WCS origin), to determine the LCS from three given rotation angles and three given translation distances, first the LCS is defined to be coincident with the WCS (having the same origin and axes as the WCS), then the LCS is translated by a vector composed of the three translation distances, and finally the origin and axes of the LCS are rotated in the WCS around the WCS origin using the rotation angles and the selected sequence of Euler angles. In the latter case (rotation is defined around the origin of the LCS), to determine the LCS from three given rotation angles and three given translation distances, first the LCS is defined to be coincident with the WCS (having the same origin and axes as the WCS), then the axes of the LCS are rotated around the origin of the WCS using the rotation angles and the selected sequence of Euler angles, and finally the origin of the LCS is translated in the WCS by a vector composed of the three translation distances.

[0034] As shown in Figure 3, for both the WCS 106 and LCS 102, the origin is defined as the projection of the tooth midline on the occlusal plane, i.e., the plane approximately passing through the cusps of the teeth. Aspects of the present disclosure contemplate that different WCS and LCS origins may be defined. However, this definition ensures that the X, Y, and Z translations correspond to the clinically used measurements of midline deviation, overjet, and overbite, respectively. For example, 0 mm of translation on the X axis means 0 midline deviation, in other words, the mandibular and maxillary midlines are aligned. Similarly, rotations around the X, Y, and Z axes correspond to pitch, roll, and yaw values, respectively, which can be used to represent the rotation of the moving jaw when communicating with the surgeon.

[0035] Table 1 below shows the definition of the six DOFs that define occlusion 108 and their distribution into three under user control and three under algorithmic control, as defined in a particular embodiment of the present invention. In other embodiments, different definitions of the six degrees of freedom can be used. However, the definitions as shown in Table 1 have proven to be highly intuitive and improve ease of use. [Table 1]

[0036] The DOFs under user control are considered fixed for the semi-automatic algorithm, which only manipulates the remaining DOFs to simulate the contact of the jaws. To fully define the occlusion, the algorithm finds a contact geometry between the fixed and moving jaw parts that constrains these remaining degrees of freedom. In general, ignoring geometrical degeneracy, a frictionless (sliding) point contact between two smooth surfaces (such as the tooth surfaces of the fixed and moving jaws) removes (or equivalently constrains) one degree of freedom from the dynamic system, as explained in Tasora, A., & Righettini, P. (2003), “Sliding Contact between Freeform Surfaces”, Multibody System Dynamics 10, 239-262. Therefore, to fully define an occlusion, the algorithm can find a contact configuration that contains a number of contact points equal to the number of DOFs under the control of the algorithm. For example, using the definition in Table 1 above, it is sufficient for the algorithm to find three contact points since the algorithm will only be manipulating the values ​​of three DOFs.

[0037] In the case of mandibular division or maxillary division, if the divided part contains a dental midline, it may be reasonable to apply the above method unchanged, except for considering that part as the moving jaw part instead of the whole jaw. However, one or more parts of the divided jaw may not contain a dental midline. For example, if the maxilla is divided into three parts, one of the lateral parts may contain only two premolars and two molars. In such cases, it may be more convenient and easier to use to place the origin of the LCS of the part at a point that is not the dental midline, as described above. Alternatively, a point in the middle of the part may be used. Furthermore, it may be more convenient to define the LCS such that the X' axis is parallel to the direction of the dentition that the part contains and tangent to the dental arc. The Y' axis is defined perpendicular to the X' axis, and the Z' axis is defined perpendicular to both the X' and Y' axes and substantially perpendicular. The X'-Y' plane will be substantially parallel to the occlusal plane. The manner in which the disclosed methods function is not materially altered by this change in definition, but it does alter the interpretation of the LCS positioning parameters as clinical measurements, as shown in Table 2 below: [Table 2]

[0038] In some cases, it may be advantageous to place an additional, fourth degree of freedom under the control of the user, reducing the number of degrees of freedom controlled by the algorithm to two. In such cases, the algorithm may constrain these two degrees of freedom by forcing the moving and fixed jaw parts to contact at fewer, e.g., two, contact points. For example, the X-rotation may be placed under the direct control of the user instead of being controlled by the algorithm, giving the user additional control with the drawback of having to manipulate an additional variable. For example, when the user repositions the entire jaw, it may be necessary to ensure that the teeth of both jaws only contact at two points on the anterior incisors and / or canines, with a gap between the molar teeth. This gap can be closed by further orthodontic treatment or bite refinement after the planned orthognathic surgery. In such cases, the contact at the anterior side can be ensured by controlling the rotation about the X-axis of the WCS (representing rotation in the sagittal plane). In other cases, e.g. mandibular split and maxillary split, if a part of the split jaw is composed of several adjacent teeth forming an approximately linear row, so that the part has a very elongated shape, the contact surface between that part (treated as the moving jaw part) and the fixed jaw part also has an elongated shape and behaves more like a line contact than an area contact. In such cases, it may not be possible to obtain a stable three-point contact, and the X-rotation determined by the algorithm (representing a rotation about the X-axis of the WCS, which is approximately parallel to the contact line) will behave unstable. By letting the user control this rotation instead of the algorithm, a more stable solution can be obtained, resulting in an occlusion where the split jaw part contacts the fixed jaw part at two points instead of three. Since the split jaw is composed of multiple parts, even if there are two contact points per part, the occlusion of the whole jaw is still stable enough, since the complete jaw has more than four contact points.

[0039] If the X rotation is under user control, then based on user inputs controlling the translation, X rotation, Z rotation, and control point positions of the moving jaw portion 100 in the XY plane, the algorithm applies certain optimization parameters (described in detail below) to calculate the vertical translation, i.e., the vertical (Z) translation. The algorithm also calculates a Y rotation acting about the approximately horizontal (Y) axis to bring the teeth into optimized contact without changing the parameters set by the user.

[0040] As mentioned above, in some embodiments, instead of fixing the LCS origin to the projection of the teeth midline on the occlusal plane, the user may be allowed to select a point that will serve as the LCS origin of the moving jaw part. This may be achieved, for example, by providing a graphical user interface (GUI) that allows the user to select a point on the three-dimensional model that represents the moving jaw part. Although the relationship between the DOF values ​​and the clinical measurements mentioned above is lost, this allows the user to determine the center of rotation of the moving jaw part, since the origin of the LCS is the point about which the moving jaw part appears to rotate when the DOFs that represent rotations about different axes are changed.

[0041] In some embodiments, a method of determining a virtual occlusion is provided. The method includes obtaining a three-dimensional representation of a first jaw part of a patient and a second jaw part of a patient, the second jaw part being opposed to the first jaw part and movable relative to the first jaw part. The method may further include setting and representing, in a graphic user interface (GUI) with the three-dimensional representation, an initial position of the first jaw part relative to the second jaw part, the initial position being defined by control points on the second jaw part having six degrees of freedom predefined relative to a coordinate system having an origin fixed relative to the first jaw part. The method may further include receiving a user input of a change to at least one of the degrees of freedom, and automatically adjusting at least one of the other degrees of freedom to minimize a distance, such as a perpendicular distance of the control points relative to the origin, while constraining the distance between the opposed surfaces of the first and second jaw parts to be positive, thereby determining an occlusion between the first and second jaw parts. The method may further include representing, in the GUI, the first and second jaw parts in the determined occlusion.

[0042] In some embodiments, the user input of the modification includes a change, such as a positive or negative change, to at least one of the position of the second jaw part in an X direction in a coordinate system corresponding to a patient's left direction, the position of the second jaw part in a Y direction in a coordinate system corresponding to a patient's rear direction, and the position of the control point for the second jaw part.

[0043] In some embodiments, the user input of the modification includes a change, such as a positive or negative change, to at least one of the position of the second jaw part in an X direction in a coordinate system corresponding to a patient's left direction, the position of the second jaw part in a Y direction in a coordinate system corresponding to a patient's back direction, the orientation of the second jaw part about a Z direction in a coordinate system corresponding to a patient's up direction, the position of the control point relative to the second jaw part.

[0044] In some embodiments, the user input of a change to a position of the control point relative to the second jaw part includes a change to a position of the control point in a Y' direction in a local coordinate system of the second jaw part. In some embodiments, the user input of a change to a position of the control point relative to the second jaw part includes a change to a position of the control point in one or more of an X', Y' and Z' direction in a local coordinate system of the second jaw part.

[0045] In some embodiments, the user input of modifications includes modifications, such as a positive or negative change, to at least one of the position of the second jaw part in an X direction in a coordinate system corresponding to a patient's left direction, a rotation of the second jaw part about the same X direction, the position of the second jaw part in a Y direction in a coordinate system corresponding to a patient's back direction, a rotation of the second jaw part about a Z direction in a coordinate system corresponding to a patient's up / down direction, and a position of the control point for the second jaw part.

[0046] In some embodiments, the user input of the modification includes at least one change, such as a positive or negative change to at least one of the position of the second jaw part in the X direction in a coordinate system corresponding to a medio-distal direction parallel to the dental arc, the rotation of the second jaw part about the same X direction, the position of the second jaw part in the Y direction in a coordinate system corresponding to a buccolingual direction perpendicular to the dental arc, the rotation of the second jaw part about the Z direction in a coordinate system corresponding to the patient's superior-inferior direction, and the position of the control point relative to the second jaw part.

[0047] In some embodiments, the user input of a change in position of the control point relative to the second jaw part comprises a change in position of the control point in an X' direction in a local coordinate system of the second jaw part.

[0048] In some embodiments, the first jaw portion includes the patient's upper jaw and the second jaw portion includes the patient's lower jaw.

[0049] In some embodiments, the first jaw portion includes a lower jaw of the patient and the second jaw portion includes an upper jaw of the patient.

[0050] In some embodiments, the first jaw portion includes the patient's upper jaw and the second jaw portion includes a portion of the patient's lower jaw resulting from a split mandibular osteotomy.

[0051] In some embodiments, the first jaw portion includes the patient's mandible and the second jaw portion includes a portion of the patient's maxilla resulting from a split maxillary osteotomy.

[0052] In some embodiments, the first jaw portion includes a portion of the patient's maxilla resulting from a maxillary split osteotomy, and the second jaw portion includes a portion of the patient's mandible resulting from a mandibular split osteotomy.

[0053] In some embodiments, the first jaw portion includes a portion of the patient's mandible resulting from a mandibular split osteotomy, and the second jaw portion includes a portion of the patient's maxilla resulting from a maxillary split osteotomy.

[0054] In some embodiments, the GUI includes a representation, such as a visualization, of a three-dimensional model of each of the first and second jaw portions.

[0055] In some embodiments the GUI further comprises an occlusal image of at least one of the first jaw portion and the second jaw portion.

[0056] In some embodiments, the GUI further includes a display of the two or three contact points determined by the algorithm, e.g., showing dots at the locations of the contact points superimposed on the three-dimensional model of the first and second jaw parts and / or on the bite image.

[0057] In some embodiments, the GUI further includes display of additional approximate contact points, defined as points of the moving jaw part whose distance to a corresponding point of the fixed jaw part is below a predetermined threshold (e.g., a threshold between 0 mm and 1 mm, more specifically, a threshold of 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm) while both jaws are in occlusion. Displaying these points can indicate areas of teeth that are in approximate contact and areas that may be in physical contact if the jaws are flexible. The approximate contact points can be displayed, for example, by superimposing them on the three-dimensional model of the first and second jaw parts and / or on the occlusal image in a color different from the color used for the two or three contact points determined by the algorithm, and displaying a point at that location. Optionally, only selected (approximate) contact points can be displayed. For example, the most relevant approximate contact points can be selected by projecting all approximate contact points onto the LCS X'-Y' plane, determining the two-dimensional convex hull of the projection points, and selecting only those approximate contact points whose corresponding projection points lie on the boundary of the two-dimensional convex hull. To reduce visual clutter, only selected approximate contact points may be displayed, which has the effect of eliminating a large number of points in the interior of the two-dimensional shape formed by the projected points, while preserving the outer boundary that indicates the extent of the shape.

[0058] In some embodiments, the GUI further comprises a display of interactive user controls corresponding to the degrees of freedom controlled by the user. In some embodiments, these interactive user controls form part of the visualization of the three-dimensional model. In other embodiments, these interactive user controls form part of a separate window region of the GUI.

[0059] In some embodiments, the GUI further includes an indication of values ​​corresponding to the automatically adjusted degrees of freedom.

[0060] In some embodiments, the GUI further includes display of a control that allows the user to switch between manipulating single portions resulting from the division of either the upper or lower jaw, and manipulating all portions of the entire jaw as a whole, with the relative positions and orientations of those portions remaining fixed.

[0061] In some embodiments, while manipulating a single portion resulting from a division of either the upper or lower jaw, the GUI further includes display of a control to enable or disable visualization of portions of the same jaw that are not being manipulated.

[0062] In some embodiments, the GUI further includes display of a control that determines whether the rotation about the WCS X-axis is determined by the user or by an algorithm.

[0063] In some embodiments, the GUI further comprises the display of interactive user controls that allow the user to select a three-dimensional point on the moving jaw to be used as the LCS origin.

[0064] In some embodiments, before determining the occlusion, the user can indicate the maximum allowable depth of burring on the occlusal surface of the three-dimensional model of one or both jaws. This can be accomplished, for example, by having the user select the maximum depth of burring and having the user apply a paintbrush-like tool to mark the section of the tooth surface corresponding to the area where this maximum depth is to be applied. Many other ways of interactively indicating the area with the maximum allowable depth of burring are possible. For example, the user can use a lasso tool or a polygonal lasso tool. Alternatively, the user can specify a line in the XY plane of the LCS or WCS. The area of ​​the tooth surface anterior or posterior to a vertical plane (parallel to the Z axis) passing through this line can be used as said area. Once this burring area is selected, the maximum depth of burring can be applied by modifying the three-dimensional model representing the affected jaw such that the parts of the three-dimensional model representing the selected area, for example the points or triangles that make up the surface of the three-dimensional model, are translated in a direction towards the inside of the model, thereby generating a modified three-dimensional model. This direction can be the same for all points and triangles within the region, e.g., in the vertical (Z) direction translating downwards for the mandible and upwards for the maxilla. Alternatively, a surface offset with a negative distance value can be applied to the portion of the 3D model representing the selected region. After generating one or more modified 3D models in this way, they can be used in the semi-automatic virtual bite algorithm instead of the corresponding original 3D models.

[0065] After the modified three-dimensional model representing the jaws is generated to apply the maximum burring depth, the occlusion image can be calculated in two different ways. Either version may be displayed to the user, or both versions may be displayed simultaneously. In certain embodiments, both versions are calculated in the same way as if the three-dimensional model had not been manipulated, but the three-dimensional model used as input for the underlying distance calculation is different. The first version of the occlusion image uses the modified three-dimensional model for the parts of the jaw where the modified three-dimensional model is available, and the original three-dimensional model for all the remaining jaw parts. Because the same three-dimensional model is used in the semi-automatic algorithm that simulates contacts, all distances between both three-dimensional models displayed in the occlusion image are zero or greater than zero. These distances quantify how much space there will be between the teeth of both jaws when they are burred to the maximum burring depth indicated, over the entire area indicated by the user. The second version of the occlusion image uses the original three-dimensional model, before any manipulation to apply the maximum burring depth, for all the jaw parts, but with the relative positions and orientations determined by applying the semi-automatic algorithm that simulates contacts to the modified three-dimensional model. As a result, the distance between both 3D models displayed in the occlusal image can be less than zero in some areas of the occlusal surfaces of the teeth, indicating that there is interpenetration between the 3D models of both jaws in those areas. The absolute value of these negative distances indicates the actual burring depth required to obtain the occlusion calculated by the contact simulation algorithm.

[0066] 10A-D show cases where localized burring is desired. FIG. 10A shows a side view of a three-dimensional model representing the upper jaw 104 and the lower jaw 100, with the occlusal planes shown in solid lines. The three-dimensional models of the upper and lower jaws are shown in a desired occlusion with contact at two points 142, shown as dots. However, in this desired occlusion, the occlusal planes of both jaws interfere at two locations 148. The user may wish to remove this interference by removing a portion of the teeth of one or both jaws by burring. Without modifying the three-dimensional model, the method disclosed herein can determine the occlusion, as shown in FIG. 10B, which includes contact at an undesired location 143, shown as a diamond. To avoid such a situation, the user can indicate an area with a maximum burring depth. As depicted in FIG. 10C, a modified three-dimensional model 150 can be generated, for example, based on the original three-dimensional model of the upper jaw 104, by applying an inward offset beyond the maximum burring depth d to the indicated area, shown as a dashed line. As a result, the modified three-dimensional model 150, shown in solid lines, can be used to determine the occlusion. Fig. 10D shows the resulting occlusion. This result coincides with the desired occlusion. The mandibular three-dimensional model 100 contacts the modified maxillary three-dimensional model 150 at the two desired contact points 142 and does not interfere in other positions. The original maxillary three-dimensional model 104 (dashed lines) interferes with the mandibular 100 in the same occlusal pose. The negative distance d' between both models indicates the actual burring depth required to obtain this occlusion.

[0067] In some embodiments, the method further includes updating the representation of the first and second jaw parts in the GUI of the determined occlusion in response to additional user input of a change to at least one of the degrees of freedom and a corresponding automatic adjustment of at least one of the other degrees of freedom.

[0068] In some embodiments, a method of forming a surgical guide based on the determined virtual occlusion is provided. The method includes obtaining a three-dimensional representation of a first jaw portion of a patient and a second jaw portion of the patient, the second jaw portion opposing the first jaw portion and movable relative to the first jaw portion. The method may further include using the three-dimensional representation to set an initial position of the first jaw portion relative to the second jaw portion, the initial position being defined by a control point on the second jaw portion having six degrees of freedom predefined relative to a coordinate system having an origin fixed relative to the first jaw portion. The method may further include receiving a user input of a change to at least one of the degrees of freedom. The method may further include automatically adjusting at least one of the other degrees of freedom to minimize a perpendicular distance of the control point relative to the origin while constraining the distance between the opposing surfaces of the first jaw portion and the second jaw portion to be positive, thereby determining the occlusion between the first jaw portion and the second jaw portion. The method may further include forming a customized surgical guide to guide the patient's teeth into the determined occlusion during orthognathic surgery.

[0069] In some embodiments, the method further includes representing the first and second jaw parts in the determined occlusion in a graphic user interface (GUI).

[0070] Also disclosed herein are systems for carrying out any of the methods disclosed herein. Also disclosed herein is a non-transitory computer-readable storage medium having instructions stored therein that, when executed by a computing device, cause the computing device to perform any of the methods disclosed herein.

[0071] Also disclosed herein is a computer program comprising instructions that, when executed by a computing device, cause the computing device to perform any of the methods disclosed herein.

[0072] The following description and the related drawings set forth in detail certain illustrative features of the one or more embodiments. [Brief description of the drawings]

[0073] The accompanying drawings depict certain aspects of the one or more embodiments and therefore are not to be considered as limiting the scope of the disclosure. [Figure 1] Figure 1 shows an example of a conventional workflow for determining a desired occlusion for orthognathic surgery planning; [Figure 2] Figure 2 shows an example of another conventional workflow for determining a desired occlusion for orthognathic surgery planning; [Figure 3] Figure 3 shows an example of a defined coordinate system for the moving and fixed jaws; [Figure 4] Figure 4 shows an example of a moving jaw and a fixed jaw with various points used to optimize the occlusion; [Figure 5] Figure 5 shows an example of a graphic user interface (GUI) for determining and displaying a virtual occlusion; [Figure 6] Figure 6 shows an example of details of the GUI in Figure 5; [FIG. 7A] FIG. 7A shows an example of a generalized diagram of a semi-automatic method for determining a virtual occlusion; [FIG. 7B] FIG. 7B shows an example of a block diagram showing a schematic overview of a system for determining a virtual occlusion; [FIG. 7C] FIG. 7C shows an example of a block diagram outlining a schematic of a system for determining a virtual occlusion; FIG. 8 is a diagram showing an example of a series of steps for determining a virtual occlusion. [Figure 9] Figure 9 shows an example of a moving and fixed jaw with various points used to optimize occlusion in a salivary maxilla example; [FIGS. 10A-D] FIGS. 10A-D show examples of localized burring to obtain a desired occlusion; [FIGS. 11A and 11B] FIGS. 11A and 11B are close-ups of occlusal images of the upper jaw. FIG. 12 illustrates an exemplary three-dimensional shape of a surgical guide based on the determined occlusion.

[0074] To facilitate understanding, the same reference numerals have been used, wherever possible, to designate identical elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further description. [Detailed explanation]

[0075] Aspects of the present disclosure provide an apparatus, method, processing system, and computer-readable medium for determining a virtual occlusion for orthognathic surgery planning. The embodiments described herein solve several problems of conventional systems and methods.

[0076] The embodiments disclosed herein generally follow the coordinate system definitions in Table 1 for use cases where the moving jaw includes a central incisor, and in Table 2 for use cases where the moving jaw does not include a central incisor. However, it should be noted that proper functioning of the systems and methods disclosed herein does not depend on any particular definition or naming convention of the world or local coordinate systems. In certain aspects, operation of the systems and methods disclosed herein may be more intuitive, convenient, or user-friendly by aligning the axes of the coordinate system with clinically relevant directions, or by locating the origin of the coordinate system at a clinically relevant location. However, to benefit from such advantages, it is not important which axes in particular are aligned with such clinically relevant directions. Descriptions focusing on specific axes are meant to reflect clinically relevant directions rather than axes. For example, the embodiments disclosed herein may be described based on a coordinate system definition that aligns the X axis with the left / right direction of the patient, the Y axis with the posterior / anterior direction of the patient, and the Z axis with the superior / inferior direction of the patient. In this example, a statement such as "movement is restricted along the Y axis" is meant to be understood as "movement is restricted along the posterior / anterior direction." Although axis naming conventions differ, similar benefits can be achieved by paying attention to clinically relevant positions and orientations.

[0077] The disclosed embodiments allow for semi-automatic control of the occlusion 108 by splitting the six degrees of freedom into three that are under the control of the user, such as via a GUI or other suitable interface, and three that are manipulated by the semi-automatic algorithm. Specifically, the user can control translation in the horizontal plane (along the X and Y axes) and rotation about the vertical axis (Z axis). The algorithm does not modify these, but calculates the vertical translation (along the Z axis) and rotation about two horizontal axes (X and Y axes) to bring the teeth into three-point contact. Additionally, the user controls the position of a control point 110 on the moving jaw portion 100, which indirectly affects the algorithm. The control point 110 represents the pressure application point on the moving jaw portion 100.

[0078] This division of six degrees of freedom into user-controlled and semi-automated controlled parameters can be compared to the physical placement of an object on a non-flat, nearly horizontal surface: translation in the horizontal plane (X and Y) and rotation about a vertical axis (Z) allow the user to control where the object is placed on the surface and how it is oriented. The other three degrees of freedom (vertical translation and rotation about X and Y) are determined by how the object moves under gravity until it comes to rest on three contact points. In this comparison, control point 110 represents the center of gravity, the point that pushes the object down. If control point 110 is moved far enough, the object will tip over until it comes to rest on a different set of three contact points. The user can control the position of control point 110. In some embodiments, the user only controls the position of control point 110 in the Y direction, e.g., the anterior-posterior direction, using the coordinate system definition in Table 1. In some embodiments, the user only controls the position of control point 110 in the X' direction, e.g., the medial / distal direction, using the coordinate system definition in Table 2. However, alternative embodiments may provide user control of the position of the control point 110 in all directions.

[0079] According to a particular embodiment, the semi-automatic algorithm for simulating interdental contact is an iterative optimization algorithm. The optimization algorithm manipulates three variables (three degrees of freedom that are not under user control) to maximize the vertical displacement (Z direction in the WCS 106) of the control point 110 on the moving jaw part 100 in order to close the jaws 100, 104 together. For example, if the lower jaw is set as the moving jaw part 100, maximizing the Z position will push the jaws 100, 104 together. For the upper jaw set as the moving jaw part 100, minimizing the Z position will push the jaws 100, 104 together. Additionally, the optimization algorithm is constrained by collisions between the moving and fixed jaw parts. This is achieved by prohibiting part or all of the surface of the moving jaw part 100 from passing part or all of the surface of the fixed jaw part 104. For example, in an embodiment where both jaw parts are represented by triangular meshes, the optimization algorithm may be constrained such that a collision vertex 112 defined on the surface of the moving jaw part 100 cannot pass through a collision triangle 114 defined on the surface of the fixed jaw part 104. Alternatively, the collision vertex 112 may be defined on the surface of the fixed jaw part 104 and the collision triangle 114 may be defined on the surface of the moving jaw part 100. Because the optimization algorithm controls exactly three DOF variables, and generally (ignoring degenerate cases) each point-triangle pair constrains a single DOF, and thus exactly three point-triangle pairs constrain the solution, the result is unique and is determined entirely by the parameters under user control (the three DOFs and the position of the control points 110). To avoid a degenerate solution, e.g., the jaws 100, 104 being placed so far apart that no collision triangle 114 can be found that constrains the solution, in some embodiments the moving jaw part 100 may be prevented from moving too far away so that it becomes a degenerate solution. It should be noted that the use of a triangular mesh is not required. Other representations of the three-dimensional shape data of the moving and fixed jaw portions may be utilized in certain embodiments. For example, other types of surface elements, such as freeform surface elements, may be used to represent the jaw portions. The optimization algorithm then determines three surface element pairs.

[0080] As discussed, in certain aspects, three DOFs are described that are under user control and three that are manipulated by a semi-automatic algorithm, however, in some aspects, four DOFs may be under user control and two that are manipulated by a semi-automatic algorithm, as also discussed. For example, other embodiments of the present disclosure allow for alternative semi-automatic control of occlusion by splitting the six DOFs into four that are under user control and two that are manipulated by a semi-automatic algorithm, such as via a GUI or other suitable interface. Specifically, the user can control translation in the horizontal plane (along the X and Y axes) and rotation about a vertical axis (Z axis) and a horizontal axis (X axis). The algorithm does not modify these and calculates a vertical translation (along the Z axis) and a rotation about another horizontal axis (Y axis) to bring the teeth into two-point contact. Additionally, the user controls the position of a control point of the moving jaw part, which indirectly affects the algorithm. The control point represents a pressure application point on the moving jaw part.

[0081] In this alternative semi-automatic control method, the effect of the control points is similar to that in the three-point contact algorithm described above, except that the moving jaw part contacts the stationary jaw part at two contact points instead of three, and the control points determine at which set of points (instead of three) the contact occurs. The rotation about the X axis (left-right according to the coordinate system definition in Table 1, or tangent to the dentition arc according to the coordinate system definition in Table 2) is fixed by the user, so the position of the control points does not affect it. As a result, the position of the control points in the Y direction (anterior-posterior or perpendicular to the dentition arc) does not affect the algorithm, and it is sufficient to have the user control only the position of the control points in the X direction (left-right or mid-distal, respectively).

[0082] According to such an embodiment, as with the embodiment described above, the semi-automatic algorithm for simulating interdental contact is an iterative optimization algorithm. The optimization algorithm manipulates two variables (two degrees of freedom that are not under user control) to maximize the vertical displacement (Z direction in the WCS) of a control point on the moving jaw part to close the jaws together. For example, if the lower jaw is set as the moving jaw part, maximizing the Z position will push the jaws together. If the upper jaw is set as the moving jaw part, minimizing the Z position will push the jaws together. Additionally, the optimization algorithm is constrained by collisions between the moving and fixed jaw parts. This is accomplished by prohibiting any or all of the surface of the moving jaw part 100 from passing through any or all of the surface of the fixed jaw part 104. For example, in an embodiment in which both jaw parts are represented by triangular meshes, the optimization algorithm may be constrained such that a collision point defined on the surface of the moving jaw part cannot pass through a collision triangle defined on the surface of the fixed jaw part. Alternatively, a collision vertex 112 may be defined on the surface of the fixed jaw part 104 and a collision triangle 114 may be defined on the surface of the moving jaw part 100. Since the optimization algorithm controls exactly two DOF variables, and generally (ignoring degenerate cases) each point-triangle pair constrains a single DOF, and thus exactly two point-triangle pairs constrain the solution, the result is unique and is determined entirely by the parameters under user control (the four DOFs and the control point positions). To avoid a degenerate solution, e.g., the jaws being placed so far apart that no collision triangles can be found to constrain the solution, some embodiments may prevent the moving jaw portion from moving too far, resulting in a degenerate solution. As with other embodiments, it should be noted that the use of a triangular mesh is not required. Other representations of the three-dimensional shape data of the moving and fixed jaw portions may be utilized in certain aspects. For example, other types of surface elements, such as freeform surface elements, may be used to represent both jaw portions. The optimization algorithm then determines two surface element pairs.

[0083] Many well-known optimization techniques can be used to implement the embodiments described herein, such as gradient descent, Nelder-Mead (Gao and Han 2012), Powell (Powell 1964), or brute force search. As long as the optimization algorithm produces correct results within the constraints described herein, the choice of optimization algorithm only affects the execution time of the algorithm and, as a result, the responsiveness of the GUI.

[0084] Regardless of the optimization approach selected, contact simulation is specified as an optimization problem. As can be seen in Figure 4 (and Figures 7A and 7B), the algorithm solves the optimization problem as follows:

[0085] First, the optimization variables are the three degrees of freedom under the control of the algorithm (for WCS106, X rotation, Y rotation, and Z translation).

[0086] The objective function to be minimized is then the Z coordinate of the control point 110 defined on the moving jaw portion 100. If the lower jaw is the moving jaw portion 100, a negative Z coordinate is used, so that minimizing the value of the objective function maximizes the vertical displacement of the control point from its initial position in the direction of jaw closing. The optimization function may be either a minimizer or a maximizer. According to a particular embodiment, a minimizing optimization function is used. The same optimization function may alternatively yield a maximum value by multiplying by -1. If the lower jaw is the moving jaw portion 100, the Z position of the control point 110 may be maximized, and in such a case the negative of the Z position may be the optimization metric, since minimizing -Z corresponds to maximizing Z.

[0087] Third, for each collision point, inequality d iOptimization is applied to the set of i > 0, where di is the signed distance 116 from the collision vertex 112 (on the moving jaw part 100) indexed by i to any nearest point of the collision triangle 114 (on the fixed jaw part 104), where the sign is positive if the collision point is outside the fixed jaw part. As mentioned above, alternatively, the collision vertex 112 can be defined on the fixed jaw part 104 and the collision triangle 114 can be defined on the moving jaw part 100.

[0088] Similarly, in an embodiment in which the user can manipulate four degrees of freedom, including rotation about the X axis, as shown in FIG. 7C, the contact simulation is specified as an optimization problem.

[0089] First, the optimization variables are the two degrees of freedom (Y rotation and Z translation in WCS106) that are under the control of the algorithm.

[0090] The objective function to be minimized is then the Z coordinate of the control point 110 defined on the moving jaw section 100. If the lower jaw is the moving jaw section 100, a negative Z coordinate is used, so that minimizing the value of the objective function maximizes the vertical displacement of the control point from its initial position in the direction of jaw closure. The optimization function may be either a minimizer or a maximizer. According to a particular embodiment, a minimizing optimization function is used. The same optimization function may alternatively yield a maximum value by multiplying by -1. If the lower jaw is the moving jaw section 100, the Z position of the control point 110 may be maximized, and in such a case the negative of the Z position may be the optimization metric, since minimizing -Z corresponds to maximizing Z.

[0091] Third, for each collision point, the inequality d i≧0, where di is the signed distance 116 from the collision vertex 112 (on the moving jaw portion 100) indexed by i to any nearest point of the collision triangle 114 (on the fixed jaw portion 104), with the sign being positive if the collision point is outside the fixed jaw portion. As mentioned above, alternatively, the collision vertex 112 may be defined on the fixed jaw portion 104 and the collision triangle 114 may be defined on the moving jaw portion 100.

[0092] An example screenshot of a GUI according to an embodiment of the present disclosure is shown in Figure 5. The GUI, for example, performs two functions: 1) allowing the user to modify the three or four user-controlled DOFs and control points, and 2) displaying to the user the occlusion calculated by the semi-automatic algorithm.

[0093] In the example shown in Figure 5, the GUI provides a set of simple buttons 126 that increase or decrease the value of each DOF by a certain amount (themselves specified using spin box GUI elements). According to one embodiment, the control point 110 is specified by its Y coordinate, which is controlled in the same way as the other three degrees of freedom, but the X and Z coordinates remain zero.

[0094] The resulting occlusion calculated by the algorithm is displayed to the user via the GUI as a three-dimensional model 134 of both jaws 100, 104 and two occlusion images 136, 138. The occlusion image 136 shows a bottom-up view of the upper jaw (in the example shown and described, the fixed jaw part 104). The occlusion image 138 shows a top-down view of the lower jaw (in the example shown and described, the moving jaw part 100). Although not shown in FIG. 5, the occlusion images 136 and / or 138 can show the vertical distance between the teeth as a color plot superimposed on the view of the respective jaw parts 100, 104. Alternatively or additionally, the distance may be displayed as a color map superimposed on the three-dimensional model. It is useful if the GUI offers the possibility to selectively show or hide individual jaw parts in the three-dimensional model. The GUI can also visualize the contact points 142 and / or approximate contact points 144 on the occlusion image and / or the three-dimensional model, for example by dots or diamonds. The GUI may further visualize a convex hull 146 around the contact point 142 and / or the approximate contact point 144. In case of two-point contact, the convex hull 146 around the contact point 142 is a line segment connecting the two contact points. In case of three-point contact, the convex hull 146 is a triangle connecting the three contact points 142. The convex hull around the approximate contact point 144 may be calculated as described above and may be visualized, for example, as a polygon. The GUI may allow the user to select which convex hull 146 to visualize. Visualizing the convex hull 146 may provide the user with additional insight into the general stability of the occlusion. The GUI may further provide the user with the possibility to indicate the area with the maximum burring depth, as described above. The GUI may then further provide the user with the possibility to select between an occlusion image based on a modified three-dimensional model with the maximum burring depth applied, as described above, or an occlusion image based on the original three-dimensional model. Alternatively, the GUI may display both types of occlusion images simultaneously. The GUI may furthermore offer the user the possibility to indicate areas where a touch point should be or areas where a touch point should not be, as will be described below.The specific implementation of these features is not essential to the embodiments described herein; it is only important that the three or four DOF values ​​and control point positions are uniquely specified by the user and the resulting occlusion 108 is presented to the user.

[0095] 11A and 11B are close-ups of an occlusal image 136 of the upper jaw 104. Darker colors indicate a closer distance from the occlusal surface of the upper jaw to the occlusal surface of the lower jaw. In FIG. 11A, three contact points 142, shown as dots, are displayed where the distance between the upper and lower jaw is zero, as determined by a semi-automatic contact simulation algorithm. Additional approximate contact points 144, shown as diamonds, where the distance is below a threshold, are also shown, along with a dashed convex hull 146 of all the approximate contact points. FIG. 11B shows the same occlusal image 136, but with less visual clutter, by showing only the contact points 142 (only one in this example) and the approximate contact points 144 that lie on the convex hull.

[0096] FIG. 6 is a detailed view of button 126 of the example GUI shown in FIG. 5. Using this example GUI, a user can adjust the midline deviation, i.e., translation in the X direction, using button 128. Similarly, a user can adjust the overjet, i.e., translation in the Y direction, using button 130. Similarly, a user can adjust the rotation in the axial plane, i.e., rotation about the Z axis, using button 132. Additionally, a user can adjust the position of the pressure point 110 in the Y direction using button 140. The GUI also displays automatically calculated parameters to provide the user and / or surgeon with detailed position information in real time. The automatically calculated overbite, i.e., translation in the Z direction, is displayed in window 118. The automatically calculated coronal rotation, i.e., rotation or roll about the Y axis, is displayed in window 120. The automatically calculated sagittal rotation, i.e., rotation or pitch about the X axis, is displayed in window 122. Presenting the DOF values ​​in the GUI using clinically relevant captions can make the GUI more intuitive, useful, and user-friendly. 6, however, buttons 118, 120, 122 for the automatically calculated three DOF values ​​are disabled. In embodiments where the user has control over an additional fourth degree of freedom value, such as sagittal rotation, the corresponding button is not disabled.

[0097] In addition to or as an alternative to the set of buttons 126, the GUI may provide interactive controls for three or four user-controlled DOF values ​​superimposed on the three-dimensional model 134, such as straight arrows for translation and curved arrows for rotation.

[0098] The block diagram of FIG. 7A is a generalized view of a semi-automatic method according to an embodiment described herein. The block diagram of FIG. 7B provides an overview of a system for determining a virtual occlusion 108 according to an exemplary embodiment. Through a GUI, a user determines values ​​for three user-controlled DOFs - X translation 128, Y translation 130, and Z rotation 132- and the Y position of a control point 110 defined in the LCS 102 of the moving jaw. The other three degrees of freedom - Z translation 118, X rotation 122, and Y rotation 120- are calculated automatically by an algorithm, subject to optimization with the user-controlled degrees of freedom and constraints described herein. Those skilled in the art will readily appreciate that the block diagrams of FIG. 7A and FIG. 7B also apply mutatis mutandis to embodiments in which the user can control a different set of three degrees of freedom, or, as shown in FIG. 7C, to an embodiment in which the user can control four degrees of freedom.

[0099] The rotational degrees of freedom are used to define a set of Euler angle rotations, which, together with the translational degrees of freedom, define a mathematical transformation from the LCS 102 to the WCS 106. This transformation is applied to both the collision vertices 112 and the control points 110 (both defined on the moving object) to obtain the corresponding WCS coordinates.

[0100] The distance 116 (di) between the collision vertex 112 and the collision triangle 116 is calculated and serves as a constraint in the optimization algorithm, while the WCS Z coordinate of the control point 110 becomes the optimization objective function. Based on these, the optimization algorithm defines new estimates of the controlling DOFs, repeating the previous steps until convergence is reached. Finally, the obtained DOFs are used to define the occlusion. The occlusion is presented to the user in a GUI, where the user can evaluate the results and modify the user control parameters accordingly.

[0101] FIG. 8 is an exemplary flow chart showing a series of steps according to certain embodiments. In step 200, a three-dimensional representation of the moving jaw portion 100 and the fixed jaw portion 104 of the patient is obtained. According to certain embodiments, the three-dimensional representation may be, for example, an optical surface scan or an intraoral scan of a stone model. Alternatively, the three-dimensional representation may be obtained from a medical image, such as a CT, MRI or CBCT image. The moving jaw portion 100 may be the patient's lower jaw and the fixed jaw portion 104 may be the patient's upper jaw. Alternatively, the moving jaw portion 100 may be the patient's upper jaw and the fixed jaw portion 104 may be the patient's lower jaw. One or more of the fixed jaw portion and the moving jaw portion may be split jaws.

[0102] In step 202, the three-dimensional representation is used to graphically represent an initial position of the moving jaw part 100 relative to the fixed jaw part 104. The initial position is defined by an origin fixed relative to the fixed jaw part 104 and a control point 110 on the moving jaw part 100 having six degrees of freedom predetermined relative to the WCS 106. The WCS 106 may have an origin at the midline of the central incisors of the fixed jaw part 104. The WCS 106 may have an X-axis with a positive value toward the left of the patient. The WCS 106 may have a Y-axis with a positive value toward the posterior direction of the patient. The WCS 106 may have a Z-axis with a positive value in a vertical, upward direction. The control point 110 may be located on the Y-axis. Alternatively, for example, if the moving jaw part does not include a central incisor, the X-axis may be tangent to the dentition arc with a positive value. In the distal direction, the Y-axis is perpendicular to the X-axis and has a positive value in the lingual direction, and the Z-axis is perpendicular and has a positive value in the superior direction. Those skilled in the art will readily appreciate that other definitions may be selected, as discussed above. In certain embodiments, step 202 may further include indicating a region having a maximum burling depth and generating at least one modified three-dimensional representation 150 of at least one jaw portion by applying a medial offset to the indicated region over a distance equal to the maximum burling depth.

[0103] In step 204, a user input of a change to at least one of the degrees of freedom is received. The user input may be received via a GUI. The user input may be a change to at least one of a translation of the moving jaw portion 100 relative to the fixed jaw portion 104 in the X direction, a relative translation of the moving jaw portion 100 relative to the fixed jaw portion 104 in the Y direction, a rotation of the moving jaw portion 100 relative to the fixed jaw portion 104 about the Z axis, and a position of the control point 110 along the Y axis, for example.

[0104] In step 206, in response to the user input, at least one of the other degrees of freedom is automatically adjusted to determine the virtual bite 108 to minimize the vertical distance between the fixed jaw portion 104 and the moving jaw portion 100, possibly in a modified form to reflect the maximum burring depth. The vertical distance may be the distance in the Z direction from the control point 110 to the origin of the WCS. The automatic adjustment may be constrained such that the distance between the opposing faces of the moving jaw portion 100 and the fixed jaw portion 104 is positive. The automatically adjusted degrees of freedom may be at least one of the following: translation in the Z direction of the moving jaw portion 100 relative to the fixed jaw portion 104, rotation about the X axis of the moving jaw portion 100 relative to the fixed jaw portion 104, and rotation about the Y axis of the moving jaw portion 100 relative to the fixed jaw portion 104.

[0105] In another embodiment, in step 204, a user input of a change to at least one of the degrees of freedom is received. The user input can be received via a GUI. The user input can be a change to at least one of a translation of the moving jaw portion 100 relative to the fixed jaw portion 104 in the X direction, a translation of the moving jaw portion 100 relative to the fixed jaw portion 104 in the Y direction, a rotation of the moving jaw portion 100 relative to the fixed jaw portion 104 about the X axis, a rotation of the moving jaw portion 100 relative to the fixed jaw portion 104 about the Z axis, and a position of the control point 110, for example along the X axis.

[0106] In such a different embodiment, in step 206, in response to the user input, at least one of the other degrees of freedom is automatically adjusted to minimize the vertical distance between the fixed jaw portion 104 and the moving jaw portion 100 and determine the virtual occlusion 108, possibly in a modified form to reflect the maximum burring depth. The vertical distance may be the distance in the Z direction from the control point 110 to the origin. The automatic adjustment may be constrained such that the distance between the opposing surfaces of the moving jaw portion 100 and the fixed jaw portion 104 is positive. The automatically adjusted degree of freedom may be at least one of the translation of the moving jaw portion 100 relative to the fixed jaw portion 104 in the Z direction and the rotation of the moving jaw portion 100 relative to the fixed jaw portion 104 about the Y axis.

[0107] In step 208, the moving jaw portion 100 and the fixed jaw portion 104 are rendered in a determined occlusion 108. This may include, for example, displaying the original and / or modified three-dimensional representations of the jaw portions in the determined occlusion 108 and / or displaying one or more occlusion images. The one or more occlusion images may be based on distance measurements between the original three-dimensional representations, the modified three-dimensional representations, or a combination of both. The above steps may be performed iteratively to render a new determined occlusion 108 in response to each modification input by the user.

[0108] According to certain embodiments, a surgical guide may be formed based on the determined occlusion. For example, the surgical guide may be three-dimensionally printed. The surgical guide may be configured to guide the patient's teeth to a position corresponding to the determined occlusion during orthognathic surgery. For example, the surgical guide may take the form of a splint. For example, as shown in FIG. 12, a three-dimensional shape 1200 may be determined for the guide. The three-dimensional shape 1200 may be formed by first creating a substantially disk- or wedge-shaped body 1202 having an upper surface 1204, a lower surface 1206 opposite the upper surface, and an outer edge 1208. The outer edge may, for example, approximately mimic the outer offset of the contour of the dentition of the larger of the two jaws, as viewed from above. The body may have a thickness of, for example, between 1 mm and 5 mm. Next, a recess 1210 may be formed in the upper and lower surfaces that is complementary to a portion of the three-dimensional shape of the jaw portion in the determined occlusion. For example, the body may be centered in the occlusal plane, and a Boolean subtraction may be performed to subtract the three-dimensional model of the jaw portion from the body. The surgical guide can be manufactured based on this three-dimensional shape using any suitable additive manufacturing technique, such as, for example, stereolithography, selective laser sintering or selective laser melting, in any suitable material, such as a biocompatible polymer or metal.

[0109] According to certain embodiments, the unique way in which the components interact improves the determination of the virtual occlusion 108. Specifically, the "distribution of work" between the user and the algorithm is unique, achieved by splitting the six degrees of freedom into three or four under the user's control and three or two under the algorithm's control. The degrees of freedom controlled by the algorithm are the variables that strongly influence whether the teeth will touch, with small changes moving the collision point vertically. On the other hand, changing the degrees of freedom controlled by the user will tend to move the collision point horizontally, resulting in the teeth touching at a different point.

[0110] By splitting the six degrees of freedom in this way, the system provides a "tactile" user experience that is closer to the physical act of pressing two dental impressions together. The algorithm "pushes" the teeth into three-point contact, while the user only has to do some of the positioning. The role of the control point 110 in the algorithm also contributes to this improved user experience. If the algorithm's action is interpreted as pressing the jaws together, the control point 110 is the point where the force is applied.

[0111] In embodiments where the user can manipulate four degrees of freedom to achieve two points of contact, rather than three degrees of freedom to achieve three points of contact, there is a different trade-off between the number of parameters the user must control (and therefore the burden on the user) and the degree of control the user has over the resulting occlusion, shifting the balance toward greater control. This functionality may be optionally offered to the user, as it is primarily used when a greater degree of control is required due to the patient's jaw shape or clinical conditions.

[0112] Moreover, according to some embodiments, the particular way in which the optimization algorithm is used offers unique advantages. In certain embodiments, the search space of the algorithm consists of only two or three variables, limiting the dimensionality of the problem and making it easier to solve numerically. The use of the vertical displacement of the control points as the objective function allows for a faster evaluation of the latter, since it can be expressed as a simple function of the optimization variables. This reduces the execution time of the algorithm and improves the responsiveness of the system. This thus accelerates the process of defining the virtual occlusion and allows for smooth interaction between those involved in the surgical planning process, for example, the technician and the surgeon operating the system disclosed herein.

[0113] In embodiments of the technology described herein, the process of defining a virtual occlusion can be much faster, since the user does not need to spend time bringing the teeth into contact. Moreover, the user only needs to manipulate a limited set of parameters (three or four degrees of freedom, and control points under user control), simplifying the process, reducing the need for training, and improving reproducibility. The three or four available parameters may be relevant for clinical interpretation, making their manipulation easier. Furthermore, it may allow for more natural discussions between those involved in the surgical planning process, for example, the technician and the surgeon, during an online planning session for orthognathic surgery. Furthermore, the increased speed and ease of use may allow more alternative occlusions to be compared for the same case, improving the quality of the treatment plan.

[0114] It should be understood that the particular definitions of coordinate systems and Euler angles described with respect to certain embodiments are merely examples and can be modified for use with the embodiments described herein, for example by renaming, inverting, or rotating the coordinate axes. Additionally, a different formalism can be used for the embodiments discussed herein, such as a rotation vector to represent the three-dimensional rotation between the LCS and the WCS. Each of the different embodiments can provide that the pose of the moving jaw is represented by six degrees of freedom (three rotations and three translations), three of which (two rotations and one translation) or two of which (one rotation and one translation) are manipulated by an algorithm to bring the teeth into contact, with the remaining degrees of freedom being directly controlled by the user.

[0115] The collision points and collision triangles used to represent contact between the teeth in certain embodiments discussed herein may be modified in several ways. For example, collision points may be defined on the fixed jaw instead of the moving jaw, or on both. Similarly, in certain embodiments, collision triangles may be defined on the fixed jaw instead of the moving jaw, or on both. In certain embodiments, different methods may be used to represent the distance between the jaws, such as not using points and triangles. For example, in certain embodiments, the distance between the jaws may be represented using a signed distance field defined on an implicit surface. Each of the different embodiments may provide that a series of distances between the jaw parts are calculated, distributed over the tooth surfaces of one (or both) jaws. These distances can be positive when the teeth are not touching, zero when the teeth are touching, and negative when the tooth surfaces intersect (3D objects overlap). The signs may also be reversed (positive for overlap, negative for no contact).

[0116] In certain embodiments, the optimization algorithm constrains all distance values ​​to be positive (greater than 0). Alternatively, in certain embodiments, the optimization algorithm can constrain the distance to be a (small) negative number, e.g., a number between -1 mm and 0 mm, more particularly greater than -0.1 mm, -0.2 mm, -0.3 mm, -0.4 mm or -0.5 mm. In further certain embodiments, this number can vary over the tooth surface. This is useful to ensure that teeth are in contact despite slight overlap, slight accuracy errors, or to simulate the removal of a part of a tooth, e.g., by burring.

[0117] Alternatively, in some embodiments, the optimization constraints can be replaced by one or more penalty terms that are added to the objective function. The value of these penalty terms is zero or very low when there is no contact, but can rise rapidly as the interpenetration of both surfaces increases. For this purpose, the signed distance between the points of one jaw and the surface of the other jaw can be used. In certain embodiments, the penalty term is zero for positive signed distances (points outside the surfaces) and equal to the absolute value or square of negative signed distances (points inside the surfaces, i.e. contact).

[0118] In certain embodiments, the optimization objective function can be replaced by a single numerical value that represents the "closeness" of both sets of teeth. For example, it could be the sum of the distance or squared distance between the points defined on either jaw part. Furthermore, in certain embodiments, substitution of the control points used to let the user control where both jaw parts contact is possible. In certain embodiments, the user can define one or more areas on the tooth surface where one or more contact points must be placed or where no contact points must be placed. This can be useful when contact at the incisors is not desired for clinical reasons (for example), or when contact at some teeth should be avoided. Areas on the tooth surface where one or more contact points must be placed or where no contact points must be placed can be indicated by the user using a paintbrush-like tool to mark a portion of the tooth surface. Many other ways of indicating the areas interactively are possible. For example, the user can use a lasso tool or a polygon lasso tool. Alternatively, a line on the XY plane of the LCS or WCS can be specified. The portion of the tooth surface that is anterior or posterior to a vertical plane (parallel to the Z-axis) passing through this line can be used as the aforementioned region.

[0119] In certain embodiments, the GUI or interface used for the system can differ from the exemplary GUI described herein without affecting the functionality of the system. For example, other interfaces can provide at least two functions: (1) allowing the user to select parameters under user control, e.g., three or four DOFs and control points, and (2) presenting the resulting occlusion to the user. Any interface that performs both functions can be used in combination with the techniques described herein. For example, the buttons provided as examples can be replaced with, e.g., sliders, and the occlusiongram can be replaced or supplemented by other ways of visualizing the distance between the teeth, e.g., displaying a series of cross sections or overlaying a color map on the three-dimensional model. For convenience, the GUI of any embodiment disclosed herein can provide the possibility to selectively hide or show one or more jaw parts in the three-dimensional model. Other alternative input methods to buttons on a GUI include the use of one or more input devices traditionally used to provide user input to a computer, such as a computer mouse, joystick, trackpad, touch screen, trackball, motion controller, hand-tracking device or eye-tracking device, or a six-degree-of-freedom input device such as a 3Dconnexion SpaceMouse (3Dconnexion GmbH, Munchen, Germany). When using one or more such input devices, the input values ​​of one or more degrees of freedom under the user's control in the disclosed methods can be derived directly from the corresponding axes or degrees of freedom provided by the input device. For example, X and Y translations can be directly controlled by the left / right and forward / backward movements of a computer mouse, so that when the user moves the mouse left or right, the moving jaw moves in the X direction, and when the user moves the mouse forward or back, the moving jaw moves in the Y direction. With this setup, the translation of the moving jaw in the XY plane mimics the movement of the user's mouse.At the same time, rotation about the Z axis can be controlled by, for example, a scroll wheel or another input device.

[0120] In certain embodiments, the system may utilize an augmented reality (AR) or virtual reality (VR) system, device, or part thereof, for display and / or user interaction, such as providing an interface. For example, instead of using buttons or sliders, the user may use an input method provided by the AR or VR system to manipulate the parameters under user control. In certain embodiments, the input method includes some form of motion capture performed by the AR / VR system, e.g., hand gestures or motion controllers. In certain embodiments, voice commands may be used. In certain embodiments, a combination of an AR / VR-based user interface with the embodiments discussed herein that limit user manipulation of the moving jaw to three or four degrees of freedom may be advantageous. For example, simultaneously controlling six degrees of freedom to manually set the occlusion is difficult even using motion control, but using only three degrees of freedom may reduce the number of parameters to four, for example (three degrees of freedom plus a control point). In certain embodiments, the resulting occlusion may be presented to the user as a repositioned three-dimensional model, with an occlusion gram overlaid. Additionally, the occlusion image may be overlaid on the patient. This is similar to the information displayed on a regular computer screen, but the AR / VR interface makes it easy to view the three-dimensional model from various angles. In certain embodiments, if the AR / VR system uses hand tracking for user input, the interface can closely mimic the traditional method of physically positioning a dental cast in occlusion by positioning the three-dimensional model (physical and / or virtual) to follow the user's hand. Additionally, in certain embodiments, if the AR system can track portions of the patient's upper or lower jaw, the three-dimensional model can be superimposed on the patient's face in real time. This allows the user to easily judge the repositioning of the moving jaw in relation to the shape of the patient's face.

[0121] According to an embodiment, the GUI can represent an orthognathic surgical procedure. For example, the GUI can represent a cut and reposition of a represented maxillary portion to an initial position prior to determining a virtual bite 108. Alternatively, the GUI can represent an iterative process in which the position of the cut maxillary pieces is repositioned based on a virtual bite 108 determined after each user input in one or more of three or four degrees of freedom under the user's control.

[0122] In certain embodiments, the GUI can represent an orthognathic surgical procedure in which individual portions of a split upper jaw and / or a split lower jaw are repositioned. The GUI can allow for repositioning all upper jaw or all lower jaw portions as a whole, or a single lower jaw or upper jaw portion, with the user selecting whether to reposition both jaws and whether to reposition the entire jaw (including all portions) or a single portion of a selected jaw. Based on the user's selection, either the single portion of the jaw is treated as the moving jaw portion, or all portions of the selected jaw are merged into one object and the result is treated as the moving jaw portion. This can be an iterative process, with the user alternating between repositioning individual portions of the selected jaw and repositioning the entire jaw as a whole. When moving from repositioning the individual portions to repositioning the entire jaw, the selected jaw portions can be combined such that the relative positions and orientations resulting from the repositioning of the individual portions are maintained. This can be achieved by applying a transformation to the three-dimensional geometry, e.g., the three-dimensional model (including collision points and collision triangles), such that all portions are defined in the LCS of the entire jaw. When going from repositioning the entire jaw to repositioning individual parts, this operation can be reversed by representing all parts in their individual local coordinate systems while setting the location of the LCS origin and the orientation of the LCS axes such that the location and orientation of the parts in the WCS remain the same as when combined into a single part representing the entire jaw. Additionally, the GUI can also allow the user to alternate between manipulating different parts of the divided mandible or divided maxilla. While the user is manipulating one part, based on preference, if selected by the user, the GUI may or may not visualize other jaw parts that the user is not manipulating.

[0123] Although certain embodiments are described with respect to orthognathic surgery, the techniques discussed herein are equally applicable for planning orthodontic treatment based on intraoral scans (including plaster casts) or other suitable procedures, such as craniomaxillofacial procedures (e.g., trauma, reconstructive surgery, etc.), surgical procedures in which guides or implants are placed, or non-medical applications in which two parts of one or more objects need to be aligned relative to each other for a stable position.

[0124] For example, the techniques described herein can be used in the design of surgical guides (e.g., 3D printed drill guides), particularly to help identify alternative poses in which the guide may make stable contact with bone in locations other than those intended by the surgical plan.

[0125] Certain embodiments discussed herein may be implemented as a computer program executed on a computer. In certain aspects, input data to the program includes a three-dimensional model of (at least) the teeth of both jaw portions 100, 104.

[0126] To implement the program, in certain embodiments, a GUI framework is used to present the occlusion to the user and allow the user to determine values ​​for parameters under user control. Additionally, the computer program may include instructions for determining the LCS 102 from these parameters and for performing a transformation from the LCS 102 to the WCS 106. The computer program may include instructions for calculating, for each collision vertex 112, the distance to the closest point on the collision triangle 114. Finally, an optimization algorithm may be used.

[0127] The systems and methods described herein can be operated and executed by computing devices such as, for example, desktop computers, portable computers, portable electronic devices, tablet computers, smartphones, and other computerized devices. In some implementations, the methods described herein can be executed by native software applications, while in other implementations, they can be executed in a server-client implementation. For example, in some implementations, software configured to execute the methods described herein can be hosted by a remote server or cloud-based system. In some cases, various aspects of the systems and methods described herein can be distributed to different computing devices. For example, the method steps described herein related to presenting a GUI, receiving user input, and determining a virtual occlusion do not require significant computing power and are therefore suitable to be executed by mobile devices such as portable computers, portable electronic devices, tablets, etc. On the other hand, other steps, such as steps related to acquiring medical image data, converting the medical image data into a three-dimensional representation of the fixed jaw and the moving jaw, or acquiring a three-dimensional scan of the fixed jaw and the moving jaw, can be executed by more powerful computing devices such as desktop computers or workstations, or dedicated devices with image acquisition or scanning capabilities.

[0128] Additionally, the systems and methods described herein may be operated and performed by medical professionals, such as, for example, surgeons, doctors, nurses, or non-medical professionals, such as clinical engineers, design engineers, implant manufacturers, or patients (e.g., who have been briefed on the procedure prior to the actual procedure).

[0129] The foregoing description is provided to enable any person skilled in the art to practice the various embodiments described herein. The examples discussed herein are not intended to limit the scope, applicability, or embodiments defined in the claims. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments. For example, changes may be made in the function and arrangement of the elements discussed without departing from the scope of the disclosure. Various embodiments may omit, substitute, or add various steps or components as appropriate. For example, the methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. Also, features described with respect to some embodiments may be combined in some other embodiments. For example, an apparatus may be implemented or a method may be implemented using any number of the aspects described herein. Additionally, the scope of the disclosure is intended to cover such apparatus or methods implemented using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure defined herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0130] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0131] As used herein, the terms "fixed" and "stationary" may be used interchangeably.

[0132] As used herein, a phrase referring to "at least one" of a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other permutation of a, b, and c).

[0133] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" includes calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, database, or another data structure), ascertaining, and the like. "Determining" may also include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. "Determining" may also include resolving, selecting, choosing, establishing, and the like.

[0134] The methods disclosed herein include one or more steps or actions for achieving the method. The steps and / or actions of the method may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be changed without departing from the scope of the claims. Furthermore, various actions of the methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include, but are not limited to, various hardware and / or software component(s) and / or module(s), including circuits, application specific integrated circuits (ASICs), or processors. In general, where there are actions illustrated in a figure, those actions may have corresponding means-plus-function components with similar numbering.

[0135] The various example logic blocks, modules, and circuits described in connection with this disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but may also be a commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.

[0136] The processing system may be implemented with a bus architecture. The bus may include any number of interconnected buses and bridges depending on the particular application and overall design constraints of the processing system. The bus may couple various circuits including a processor, a machine-readable medium, and input / output devices. A user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also couple various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, etc. Other circuit elements known in the art will not be described further. The processor may be implemented with one or more general-purpose and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits capable of executing software. Those skilled in the art will recognize how best to implement the described functionality for a processing system depending on the particular application and the overall design constraints imposed on the overall system.

[0137] If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium. Software shall be broadly construed to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or the like. Computer-readable media includes both computer storage media and communication media, such as media that facilitate transfer of a computer program from one place to another. A processor may manage a bus and be responsible for general processing, including the execution of software modules stored in a computer-readable storage medium. A computer-readable storage medium may be coupled to a processor such that the processor can read information from the storage medium and write information to the storage medium. Alternatively, the storage medium may be integral to the processor. As an example, a computer-readable medium may include a transmission line, a carrier wave modulated by data, and / or a computer-readable storage medium having instructions stored thereon separate from a wireless node, all of which may be accessed by a processor via a bus interface. Alternatively, or in addition, the computer-readable medium, or any portion thereof, may be integrated into the processor, such as a cache and / or a general register file. Examples of machine-readable storage media may include, by way of example only, Random Access Memory (RAM), flash memory, Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. The machine-readable medium may be embodied in a computer program product.

[0138] A software module may include a single instruction, or many instructions, and may be distributed among several different code segments, different programs, and across several storage media. A computer-readable medium may include many software modules. A software module includes instructions that, when executed by a device such as a processor, cause a processing system to perform various functions. A software module may include a transmitting module and a receiving module. Each software module is distributed across a single storage device, or across several storage devices. As an example, a software module may be loaded from a hard drive into RAM when a triggering event occurs. During execution of a software module, a processor may load some of the instructions into a cache to speed up access. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to a function of a software module, it will be understood that such function is implemented by the processor when executing instructions from that software module.

[0139] The following claims are not intended to be limited to the embodiments set forth herein, but are to be accorded the full scope consistent with the language of the claims. Within the claims, reference to an element in the singular is not intended to mean "only one" unless specifically so recited, but rather, "one or more." Unless otherwise noted, the term "some" refers to one or more. Claim elements are not to be construed under 35 USC, §112(f), unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is recited using the phrase "step for." All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later become known to those of skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be generally exclusive, regardless of whether such disclosure is expressly recited in the claims.

[0140] For completeness, various aspects of the invention are described in the following numbered sections. 1. A method for determining a virtual occlusion, the method comprising: obtaining a three-dimensional representation of a first jaw portion of a patient and a second jaw portion of the patient, the second jaw portion opposing the first jaw portion and movable relative to the first jaw portion; using the three-dimensional representation to set and represent in a graphic user interface (GUI) an initial position of the first jaw part relative to the second jaw part, the initial position being defined by control points on the second jaw part having six predetermined degrees of freedom relative to a coordinate system having an origin fixed relative to the first jaw part; receiving user input of a change to at least one of said degrees of freedom; automatically adjusting at least one of the other degrees of freedom to minimize a perpendicular distance of the control point relative to the origin while constraining a distance between opposing surfaces of the first jaw part and the second jaw part to be positive, thereby determining an occlusion between the first jaw part and the second jaw part; and representing in the GUI the first jaw portion and the second jaw portion in the determined occlusion. 2. A method according to the first aspect, wherein the user input of changes includes a change to at least one of a position of the second jaw in an X direction in the coordinate system corresponding to a left direction of the patient, a position of the second jaw in a Y direction in the coordinate system corresponding to a rear direction of the patient, and a position of the control point relative to the second jaw. 3. A method according to the second aspect, wherein the user input of a change in the position of the control point relative to the second jaw comprises a change in the position of the control point in the Y direction in the coordinate system. 4. The method of the first aspect, wherein the first jaw portion includes an upper jaw of the patient and the second jaw portion includes a lower jaw of the patient. 5. The method of the first aspect, wherein the first jaw portion includes a lower jaw of the patient and the second jaw portion includes an upper jaw of the patient. 6. The method of the first aspect, wherein the GUI includes a three-dimensional model of each of the first jaw portion and the second jaw portion. 7. The method of aspect 6, wherein the GUI further includes an occlusal image of at least one of the first jaw portion and the second jaw portion. 8. A method according to the seventh aspect, wherein the GUI further includes a display of interactive user controls corresponding to the degrees of freedom controlled by the user. 9. A method according to the eighth aspect, wherein the GUI further includes an indication of values ​​corresponding to the degrees of freedom that are automatically adjusted. 10. A method according to the ninth aspect, further comprising updating the representation of the first jaw part and the second jaw part in the GUI of the determined occlusion in response to additional user input of a change to at least one of the degrees of freedom and corresponding automatic adjustment of at least one of the other degrees of freedom. 11. A method for forming a surgical guide based on a determined virtual occlusion, comprising: obtaining a three-dimensional representation of a first jaw portion of a patient and a second jaw portion of the patient, the second jaw portion opposing the first jaw portion and movable relative to the first jaw portion; setting an initial position of the first jaw part relative to the second jaw part in the three-dimensional representation, the initial position being defined by control points on the second jaw part having control points with six predetermined degrees of freedom relative to a coordinate system having an origin fixed relative to the first jaw part; receiving user input of a change to at least one of said degrees of freedom; constraining the distance between opposing surfaces of the first jaw part and the second jaw part to be positive while automatically adjusting at least one other degree of freedom to minimize a perpendicular distance of the control point to the origin, thereby determining an occlusion between the first jaw part and the second jaw part; and forming a customized surgical guide to guide the patient's teeth into the determined occlusion during orthognathic surgery. 12. A method according to the eleventh aspect, wherein the user input of changes includes a change to at least one of a position of the second jaw in an X direction in the coordinate system corresponding to a left direction of the patient, a position of the second jaw in a Y direction in the coordinate system corresponding to a rearward direction of the patient, and a position of the control point relative to the second jaw. 13. A method according to the twelfth aspect, wherein the user input of a change in position of the control point relative to the second jaw includes a change in position of the control point in the Y direction in the coordinate system. 14. The method of aspect 11, wherein the first jaw portion includes an upper jaw of the patient and the second jaw portion includes a lower jaw of the patient. 15. The method of aspect 11, wherein the first jaw portion includes a mandible of the patient and the first jaw portion includes an upper jaw of the patient. 16. The method of aspect 11, further comprising representing the first jaw part and the second jaw part in the determined occlusion in a graphic user interface (GUI). 17. The method of aspect 16, wherein the GUI further includes an occlusal image of at least one of the first jaw portion and the second jaw portion. 18. The method according to aspect 17, wherein the GUI further includes a display of interactive user controls corresponding to the degrees of freedom controlled by the user. 19. The method according to aspect 18, wherein the GUI further includes an indication of values ​​corresponding to the degrees of freedom that are automatically adjusted. 20. A method according to the nineteenth aspect, further comprising updating the representation of the first jaw portion and the second jaw portion in the GUI of the determined occlusion in response to additional user input of a change to at least one of the degrees of freedom and corresponding automatic adjustment of at least one other degree of freedom. [Brief description of the drawings]

[0141] The accompanying drawings depict certain aspects of the one or more embodiments and therefore are not to be considered as limiting the scope of the disclosure. [Figure 1] Figure 1 shows an example of a conventional workflow for determining a desired occlusion for orthognathic surgery planning; [Diagram 2] FIG. 2 shows an example of another conventional workflow for determining a desired occlusion for orthognathic surgery planning; [Diagram 3] Figure 3 shows an example of a defined coordinate system for the moving and fixed jaws; [Figure 4] Figure 4 shows an example of a moving jaw and a fixed jaw with various points used to optimize the occlusion; [Diagram 5] Figure 5 shows an example of a graphic user interface (GUI) for determining and displaying the virtual occlusion; [Figure 6] FIG. 6 shows an example of the GUI details of FIG. 5; [Figure 7A] Fig. 7A shows an example of a generalized diagram of the semi-automatic method for determining the virtual occlusion; [Figure 7B] FIG. 7B shows an example of a block diagram showing a schematic overview of a system for determining a virtual occlusion; [Figure 7C] FIG. 7C shows an example of a block diagram outlining a schematic of a system for determining a virtual occlusion; [Figure 8] FIG. 8 illustrates an example of a series of steps for determining a virtual occlusion. [Figure 9] FIG. 9 shows an example of a moving and fixed jaw with various points used to optimize occlusion in a salivary maxilla example; [Figure 10A] FIG. 10A shows an example of localized burring to obtain a desired occlusion; [Figure 10B] FIG. 10B shows an example of localized burring to obtain a desired occlusion; [Figure 10C] FIG. 10C shows an example of localized burring to obtain a desired occlusion; [Figure 10D] FIG. 10D shows an example of localized burring to obtain the desired occlusion; [Figure 11A] FIG. 11A is a close-up of the occlusal image of the upper jaw. [Figure 11B] FIG. 11B is a close-up of the occlusal image of the upper jaw. [Figure 12] FIG. 12 shows an exemplary three-dimensional shape of a surgical guide based on the determined occlusion. [Explanation of symbols]

[0142] 2. Make an impression of your teeth 4. Creating a plaster model from the impression 6 Position the plaster model in the articulator to determine and express the desired occlusion. 8 Fix the plaster model in the desired occlusion. 10 Scanning the fixed plaster model for planning 22A Scan the plaster cast separately 22B Intraoral scan of both jaws 24 Virtually determine the desired occlusion and specify the position and orientation of the jaws relative to each other 26 Depict the jaws in desired occlusion for planning purposes 100 Moving Jaw 1001, 1002, 1003 Movable split jaw part 102,1021,1022,1023 Local (moving) coordinate system 104 Fixed (or static) jaw 106,1061,1062,1063 World (fixed) coordinate system 108 Occlusion (mathematically defined as the position of the LCS in the WCS (6 degrees of freedom)) 110 Control points 112 Collision apex of moving jaw 114 Fixed Jaw Collision Triangle (2D) 116 The distance di between 112 and 114, which is positively constrained 118 Vertical (Z, overbite) movement variable 120 Coronal (Y, roll) rotation variable 122 Sagittal (X, Pitch) Rotation Variables 124 Z coordinate control point 110 minimized subject to constraint 116 126 User Control 128 Midline (X) Translation Variable 130 Overjet (Y) translation variable 132 Axial Plane (Z, Yaw) Rotation Variables 134 3D model of the jaw 136 Fixed jaw occlusion image 138 Occlusal image of moving jaw 140 Pressure Distance (Control Point Y) Variable 142,143 contact points 144 Approximate contact point 146 Convex Hull 148 Interference 150 Modified 3D Models 1200 Surgical Guide 1202 Guide body 1204 Top surface 1206 Bottom 1208 Edge 1210 Hollow

Claims

1. 1. A computer-implemented method for determining a virtual occlusion, comprising: obtaining a three-dimensional representation of a first jaw portion of the patient and a second jaw portion of the patient opposing the first jaw portion and movable relative to the first jaw portion; using the three-dimensional representation to set an initial position of the second jaw portion relative to the first jaw portion and represent it in a graphic user interface (GUI), the initial position being defined by control points on the second jaw portion, the second jaw portion having six predetermined degrees of freedom relative to a coordinate system having an origin fixed relative to the first jaw portion; receiving a user input of a change to at least one of the degrees of freedom, the user input of the change including a change to a position of the control point relative to the second jaw portion; constraining the distance between opposing surfaces of the first jaw part and the second jaw part to be positive while automatically adjusting at least one other degree of freedom to minimize the perpendicular distance of the control point relative to the origin, thereby determining the occlusion between the first jaw part and the second jaw part; and A computer-implemented method comprising representing the first jaw part and the second jaw part in the determined occlusion in the GUI.

2. the user input of the modification further includes a position of the second jaw part in a direction in the coordinate system corresponding to a left-right direction of the patient, a position of the second jaw part in a direction in the coordinate system corresponding to a front-to-back direction of the patient, or a rotation of the second jaw part about a direction in the coordinate system corresponding to a top-to-bottom direction of the patient; 2. The method of claim 1, wherein automatically adjusting at least one of the other degrees of freedom comprises automatically adjusting at least one of a position of the second jaw part in a direction in the coordinate system corresponding to an up-down direction of the patient, a rotation of the second jaw part about a direction in the coordinate system corresponding to a left-right direction of the patient, or a rotation of the second jaw part about a direction in the coordinate system corresponding to an anterior-posterior direction of the patient.

3. the user input of modifications further includes modifying at least one of a position of the second jaw part in a direction in the coordinate system corresponding to a left-right direction of the patient, a position of the second jaw part in a direction in the coordinate system corresponding to a front-to-back direction of the patient, a rotation of the second jaw part about a direction in the coordinate system corresponding to the up-down direction of the patient, or a rotation of the second jaw part about a direction in the coordinate system corresponding to a left-to-right direction of the patient; 2. The method of claim 1, wherein automatically adjusting at least one of the other degrees of freedom includes automatically adjusting at least one of a position of the second jaw part in a direction in the coordinate system corresponding to an up-down direction of the patient, or a rotation of the second jaw part about a direction in the coordinate system corresponding to an anterior-posterior direction of the patient.

4. 4. The method of claim 1, wherein the user input of a change in the position of the control point relative to the second jaw part comprises a change in the position of the control point in the direction in the coordinate system corresponding to an anterior-posterior direction of the patient.

5. the user input of modifications further includes modifying at least one of a position of the second jaw part in a direction in the coordinate system corresponding to a medial-distal direction of the patient, a position of the second jaw part in a direction in the coordinate system corresponding to a buccolingual direction of the patient, a rotation of the second jaw part about a direction in the coordinate system corresponding to a superior-subordinate direction of the patient, or a rotation of the second jaw part about a direction in the coordinate system corresponding to a medial-distal direction of the patient; 2. The method of claim 1, wherein automatically adjusting at least one of the other degrees of freedom further comprises automatically adjusting at least one of a position of the second jaw part in a direction in the coordinate system corresponding to a superior-subordinate direction of the patient, or a rotation of the second jaw part about a direction in the coordinate system corresponding to a buccolingual direction of the patient.

6. The method of claim 1 , wherein the first jaw portion includes at least a portion of the patient's upper jaw and the second jaw portion includes at least a portion of the patient's lower jaw.

7. The method of claim 1 , wherein the first jaw portion includes at least a portion of the patient's lower jaw and the second jaw portion includes at least a portion of the patient's upper jaw.

8. The method of claim 1 , wherein the GUI includes a three-dimensional model of each of the first jaw portion and the second jaw portion.

9. displaying the distance between the first jaw portion and the second jaw portion in the determined occlusion as a color map on the three-dimensional model; displaying contact points between the first jaw portion and the second jaw portion in the determined occlusion on the three-dimensional model; displaying on the three-dimensional model approximate contact points between the first jaw portion and the second jaw portion in the determined occlusion; 9. The method of claim 8, further comprising one or more of: displaying on the three-dimensional model a convex hull around contact points and / or approximate contact points between the first jaw part and the second jaw part in the determined occlusion.

10. The method of claim 1 , wherein the GUI further comprises an occlusal image of at least one of the first jaw portion and the second jaw portion.

11. displaying contact points between the first jaw portion and the second jaw portion in the determined occlusion on the occlusion image; displaying on the occlusion image an approximate contact point between the first jaw portion and the second jaw portion in the determined occlusion; and 11. The method of claim 10, further comprising one or more of: displaying on the occlusion image a convex hull around contact points and / or approximate contact points between the first and second jaw parts in the determined occlusion.

12. 2. The method of claim 1, further comprising updating the representation of the first jaw part and the second jaw part in the GUI of the determined occlusion in response to additional user input of a change to at least one of the degrees of freedom and a corresponding automatic adjustment of at least one of the other degrees of freedom.

13. receiving user input indicating a region of at least one of the first jaw portion and the second jaw portion and assigning a maximum burring depth to the region; and generating at least one modified three-dimensional model representing at least one of the first and second jaw portions based on the indicated area and the maximum burring depth; 2. The method of claim 1, wherein automatically adjusting at least one of the other degrees of freedom includes constraining a distance between opposing surfaces of the first jaw member and the second jaw member to be positive based on the at least one modified three-dimensional model.

14. The method of claim 13 , wherein the GUI includes an occlusal image of at least one of the first jaw part and the second jaw part based on the at least one modified three-dimensional model.

15. 1. A computer-implemented method for creating a surgical guide based on a determined virtual occlusion, comprising: Determining a virtual occlusion between a position of a first jaw portion and a position of a second jaw portion of a patient using the method of claim 1; forming a surgical guide for guiding the patient's teeth into the determined occlusion during orthognathic surgery.

16. 1. A system for determining a virtual occlusion, comprising: a graphic user interface (GUI); a processor, The processor:

10. The method of claim 1, further comprising: determining a virtual occlusion between a position of a first jaw portion and a position of a second jaw portion of a patient; and representing, in the GUI, the first jaw part and the second jaw part in the determined occlusion.

17. A mobile device comprising the processor; and further comprising a second computing device comprising a second processor; 17. The system of claim 16, wherein the second computing device is one of a desktop computer, a workstation, and a computing device with image acquisition or scanning capabilities.

18. A non-transitory computer-readable storage medium storing instructions that, when executed by a computing device, cause the computing device to perform the method of claim 1.

19. 10. A computer program comprising instructions that, when executed by a computing device, cause the computing device to perform the method of claim 1.

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