Computer-implemented method for arranging a plurality of physical scan bodies
Patent Information
- Application Number
- PCT/EP2026/053999
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-19
- Filing Date
- 2026-02-13
- Publication Date
- 2026-08-27
Smart Images
Figure EP2026053999_27082026_PF_FP_ABST
Abstract
Description
[0001] A COMPUTER-IMPLEMENTED METHOD FOR ARRANGING A PLURALITY OF PHYSICAL SCAN BODIES FIELD
[0002] The disclosure relates to a computer-implemented method for scanning a plurality of physical scan bodies to determine more precise positions of implants in a virtual model of a dental arch. More specifically, the computer-implemented method is about improving the arrangement of the plurality of physical scan bodies.
[0003] BACKGROUND
[0004] The use of intraoral scanning for accurately determining a position of an implant in a virtual model of a dental arch has had challenges due to inaccuracy in the digital scan that accumulates over the length of the arch due to fundamental errors made in the imaging and stitching of the depth measurements and images that build up in the virtual model. Often physical jigs have been used to validate the placement of the implant, but this kind of procedure is cumbersome and only adds to the complexity of an already extensive and long procedure.
[0005] Recently advances have been made in the strategy of assessing the final placement of the implant and positions of abutments, specifically by a type of workflow incorporating the intraoral scanner. With the use of special cantilever type scan bodies arranged on the implants, the global accuracy limitations of the intraoral scanner will pose a smaller effect upon the final result, due to a smart configuration of the scan bodies inside the mouth.
[0006] This disclosure builds on this principle and describes improvements in the workflow that significantly increase ease-of-use through advanced software integration.
[0007] SUMMARY
[0008] It is an aspect of the present disclosure to provide a more accurate method for determining the position of the implants in a virtual model of a dental arch.It is another aspect of the present disclosure to provide an easier way of arranging a plurality of scan bodies onto implants that are already implanted into the patient’s dental arch.
[0009] The disclosure relates to a computer-implemented method for arranging a plurality of physical scan bodies relative to a plurality of fiducials inserted into a dental arch of a patients’ mouth. The plurality of fiducials may include a plurality of abutments applied onto implants that are implanted into the patient’s dental arch. The plurality of fiducials may solely or further include a plurality of implants that are implanted into the patient’s dental arch. The plurality of fiducials may solely or further include a plurality of healing caps arranged onto the implants or abutments arranged inside the patient’s mouth. The plurality of physical scan bodies may have a geometrical shape that is known and used by the computer-implemented method to be identified in intraoral scan data of a dental arch, such as a first scan arch data and a second scan arch data. The method comprising providing a first scan arch data of a dental arch with a plurality of fiducials inserted in edentulous areas of the dental arch. The first scan arch data may be provided by an intraoral scanner that may be configured to provide three-dimensional data of the dental arch based on a focus scanning principle or a triangulation scanning principle. The first scan arch data (and a second scan arch data) may include either two-dimensional scan data or three-dimensional scan data which includes geometrical data of the dental arch. The first scan arch data (and the second scan arch data) may include color data of the dental arch. The computer-implemented method may further include determining, based on the first scan arch data, a first virtual model of the dental arch that includes the plurality of fiducials. The first virtual model may be a two-dimensional or a three-dimensional virtual model of the dental arch that includes the plurality of fiducials. The computer-implemented method may further include determining, based on the first scan arch data, positions of the plurality of fiducials, and based on the positions of the plurality of fiducials, positions and orientations of a plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model is determined. The positions of the plurality of fiducials may be arranged according to a two-dimensional or a three-dimensional coordinate system in which an optimal orientation of each of the plurality of virtual scan bodies may be determined. The optimal orientation may be determined such that a distalends of the plurality of virtual scan bodies form a curve that partly or fully resembles the curved shape of the dental arch which the plurality of virtual scan bodies is applied to. The plurality of virtual scan bodies may not overlap with each other, and thereby, the computer-implemented method may select, automatically, based on the position and the orientation of the plurality of virtual scan bodies, types of virtual scan bodies to be arranged on the plurality of fiducials in the first virtual model. The type of virtual scan bodies may involve different sizes or lengths of a virtual scan body of the plurality of virtual scan bodies. The selection of the plurality of virtual scan bodies is based on avoiding overlaps between the plurality of virtual scan bodies and to have an optimal distance between the distal ends of the plurality of virtual scan bodies. The optimal distance may be a minimum distance allowed by the different sizes / lengths of available physical scan bodies. In such an example, a user may be able to select, via a user interface, those physical scan bodies that are available. The user interface may be connected to one or more processing units configured to process the computer-implemented method. In another example, the optimal distance may be optimal for an easy way of arranging physical scan bodies inside a patient’s mouth according to the arrangement of the plurality of virtual scan bodies. In yet another example, the optimal distance may be optimal such that the distances between the distal ends of the plurality of virtual scan bodies are minimized to have an optimal curve shape of the distal ends of the plurality of virtual scan bodies, and also, to make it easier for the user to scan the physical scan bodies when arranged inside the patient’s mouth according to the plurality of virtual scan bodies. It is important that when scanning the plurality of physical scan bodies at least two neighbouring physical scan bodies of the plurality of physical scan bodies have to be within a scanning window of the intraoral scanner such that image frames of the scan arch data can be stitched together to form a series of two-dimensional images to form a two-dimensional model of the dental arch with the plurality of physical scan bodies. It is important that when scanning the plurality of physical scan bodies at least two neighbouring physical scan bodies of the plurality of physical scan bodies must be within a scanning window of the intraoral scanner such that image frames of the scan arch data can be stitched together to form a series of three-dimensional images to form a three-dimensional model of the plurality of physical scan bodies with or without the dental arch. To improve the ability for the user to be able to arrange the plurality of physical scanbodies according to the position and the orientation of the plurality of virtual scan bodies, the computer-implemented method may include displaying the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations relative to the plurality of fiducials.
[0010] The displaying of the first virtual model with the selected type of virtual scan bodies arranged according to the positions and orientation relative to the plurality of fiducials assists the user in the selection of a plurality of physical scan bodies to be inserted into the patient’s mouth, and, how to position and orientate each of the plurality of physical scan bodies. The selection of the plurality of physical scan bodies may be manually done by the user or done by a robotic arm that receives instructions from one or more processing units configured to process the computer-implemented method. The manually selected plurality of physical scan bodies corresponds to the selected types of virtual scan bodies.
[0011] Furthermore, the user may then arrange, manually and according to the positions and orientation of the plurality of virtual scan bodies, the selected plurality of physical scan bodies onto the plurality of fiducials in the dental arch. Then, the user may scan the dental arch with the selected plurality of physical scan bodies arranged onto the plurality of fiducials in the dental arch, and a second scan arch data of the selected plurality of physical scan bodies arranged onto the plurality of fiducials is provided. Based on the second scan arch data, a second virtual model is determined of the dental arch that includes the selected plurality of physical scan bodies arranged onto the plurality of fiducials. In an example, the second virtual model that includes the plurality of physical scan bodies arranged relative to the plurality of fiducials may be displayed.
[0012] The plurality of fiducials may include a plurality of abutments applied onto implants that are implanted into the patient’s dental arch. The plurality of fiducials may solely or further include a plurality of implants that are implanted into the patient’s dental arch. The plurality of fiducials may solely or further include a plurality of healing caps arranged onto the implants or abutments arranged inside the patient’s mouth. The plurality of physical scan bodies may have a geometrical shape that is known and used by the computer-implemented method to be identified in intraoral scan data of a dental arch, such as a first scan arch data and a second scan arch data. Each of the physical scan bodies hasa fiducial interface that is configured to be connected to a fiducial of the plurality of fiducials. The fiducial interface may be a snap coupling or a screw interface. The computer-implemented method may be configured to determine a position of a fiducial interface based on a scanned part, i.e. the second scan arch data, of a corresponding physical scan body, and based on the position of the fiducial interface, the exact position of the fiducial which the physical scan body is connected to, via the fiducial interface, can be determined. Thereby, the computer-implemented method may be configured for determining, based on the plurality of physical scan bodies in the second virtual model, new positions of the plurality of fiducials relative to the dental arch, and displaying the plurality of fiducials at the new positions in the second virtual model or in the first virtual model. The new positions of the plurality of fiducials could also be displayed on a third virtual model of the dental arch.
[0013] The type of the plurality of physical scan bodies may be determined automatically or manually and based on the types of the plurality of physical scan bodies, the position and orientation of the plurality of physical scan bodies new positions of the plurality of fiducials can be determined. The type of a physical scan body may be determined automatically by one or more processing units configured to compare a scan part of the physical scan body with a known shape of a reference geometrical part of a reference scan body. When a match between the physical scan body and a reference scan body, the reference scan body is then aligned with the physical scan body, and the exact position and / or orientation of the fiducial is determined based on the geometry of the reference scan body, and the position and the orientation of the physical scan body in which the reference scan body is aligned to.
[0014] The reference scan object may be a CAD shape of a physical scan bodies of the plurality of physical scan bodies.
[0015] The determining of the positions and orientations of the plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model may include a curved shape arrangement between distal ends of the plurality of virtual scan bodies, and wherein the distal end of each of the plurality of virtual scan bodies is distantly arranged to theplurality of fiducials. The curved shape arrangement may resemble the curved shape of the dental arch of the patient but with a smaller curved radius relative to the curved shape of the dental arch. For example, a first radius-curve of the curved shaped arrangement may be less than a second radius-curve of the dental arch in the first virtual model. By displaying the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations relative to the plurality of fiducials would provide the user an improved way of arranging the plurality of physical scan bodies such that the curved shape arrangement is obtained. An optimal curved shape arrangement provides an even more accurate determination of the new positions of the plurality of fiducials relative to the dental arch. Furthermore, the accurate determination of the positions would provide an ease-of-use, as the user does not have to un-attach the physical scan bodies if they don’t fit correctly.
[0016] The determined orientation of the plurality of virtual scan bodies may include determining line axes of the plurality of virtual scan bodies relative to the positions of the plurality of fiducials, determining an orientation of the line axes, such that at least a group of the line axes intersect at an intersection point, and determining, based on the orientation of the line axes, the types of virtual scan bodies to be arranged on the plurality of fiducials. The positions of the plurality of fiducials may be arranged according to a two-dimensional or a three-dimensional coordinate system in which an optimal orientation of each of the plurality of virtual scan bodies may be determined based on the orientation of the line axes. For example, each of plurality of fiducials may be represented by points (Pl, P2, P3, P4) along the dental arch which have a distance between that can be determined by:
[0017] -i=l^i+i—Pt \ •
[0018] The dental arch with the four points (Pl, P2, P3, P4) that represent virtual fiducials may be defined in a two-dimensional coordinate system, such that each of the points has a position (x, y) determined by the distance di between the four points and a relative angle between successive points (Pl, P2, P3, P4). A line axis may originate from each of the points at an angle towards a meeting point Pm= (xm, ym).
[0019] The equation of the line axis may be determined by following equation:(x - Xi)2+ (y - y,-)2= L2.
[0020] The line axis Li should point towards Pm, and the above equation can be written parametrically:
[0021] <
[0022]
[0023] is the direction of the line axis. To ensure that all line axes of the plurality of fiducials, i.e. the points (Pl, P2, P3, P4), meet at Pm then the following equation should be solved:
[0024] xm= Xi + Licos (ai),ym= yt+ LiSin (ai) Vi e {1,2, 3, 4}.
[0025] Since the line axes Li are discrete, the problem can be solved using brute-force search or optimization techniques, such as minimizing the sum of squared distances of the line axes’ endpoints to a common point.
[0026] To determine the Best Length Combination enumerate all possible combinations of line axes, and for each combination, solve the above equations for Pm. Check the error by computing the distance between the estimated intersection point and endpoints of the lines axes. Then, select the optimal solution that minimizes the total error.
[0027] The aligning of the scanned plurality of physical scan bodies relative to the scanned plurality of fiducials in the second virtual model comprising identifying the plurality of physical scan bodies in the second virtual model by a segmentation algorithm and determining a geometrical shape of the plurality of physical scan bodies. The segmentation algorithm may include an artificial intelligence algorithm that has been trained by knowing different type of physical scan bodies and comparing these known types with the geometrical shape of the plurality of physical scan bodies.
[0028] Furthermore, the computer-implemented method may comprise identifying the plurality of physical scan bodies by determining, based on the second scan arch data, a shape of at least a geometrical part of each of the plurality of physical scan bodies, comparing the shape of at least the geometrical part with a known shape of a reference geometrical partof a reference scan body, determining a complete shape of each of the plurality of physical scan bodies according to a shape of the reference scan body where a match shape between the geometrical part and the reference geometrical part is obtained, and wherein the segmentation algorithm is configured to segment each of the plurality of physical scan bodies based on the determined shape of the complete scan body.
[0029] The determining of the positions of the plurality of fiducials in the first virtual model is provided by a segmentation algorithm.
[0030] The computer-implemented method may comprise initiating an implant design workflow based on detection of the plurality of fiducials via the segmentation algorithm. The design workflow involves the displaying of the first and second virtual model and designing of crowns or dental bridges.
[0031] To improve the accuracy of determining the new positions of the plurality of fiducials, the computer-implemented method may comprise generating a first feedback signal, based on the second scan arch data, on whether the manually selected plurality of physical scan bodies matches the plurality of virtual scan bodies for the corresponding plurality of fiducials. Thereby, the user will be notified during the scanning of the plurality of physical scan bodies or just after the scanning, via the first feedback signal on whether the user has selected a correct physical scan body for a certain fiducial. If the selected physical scan body is not correct, then the user would be able to remove and select a new physical scan body and perform the scanning of the plurality of physical scan bodies again.
[0032] The computer-implemented method may further include determining, based on the second scan arch data and the segmentation algorithm, type of the plurality of physical scan bodies that are arranged relative to the plurality of fiducials in the second virtual model, comparing for each of the plurality of fiducials, the determined type of a physical scan body of the plurality of physical scan bodies with a virtual scan body of the plurality of virtual scan bodies for a corresponding fiducial of the plurality of fiducials, and generating a first feedback signal to a user based on the comparing between theplurality of physical scan bodies with the plurality of virtual scan bodies for each of the plurality of fiducials.
[0033] The computer-implemented method may further include generating a second feedback signal on whether two or more of the plurality of physical scan bodies are detected in a single scan frame of the second scan arch data. A single frame depicts what a scanning window of the intraoral scanner sees, and in order to determine the second virtual model of the dental arch including the plurality of physical scan bodies, then the single scan frame may need to capture at least two neighbouring physical scan bodies of the plurality of physical scan bodies.
[0034] Another aspect of the disclosure is to obtain an intraoral scanning system that comprises a memory unit that includes different geometrical shapes of a plurality of physical scan bodies and one or more processing units configured to process fully or partially the computer-implemented method. The system may further include a display unit configured to display the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations relative to the plurality of fiducials. Furthermore, the display unit may be configured to display the second virtual model.
[0035] The one or more processing units may be arranged in one or more elements of the intraoral scanning system:
[0036] • an intraoral scanner,
[0037] • an external computer that may be wired and / or wireless connected to the intraoral scanner,
[0038] • a local server, and / or
[0039] • a cloud server.
[0040] The disclosure further relates to an intraoral scanning system configured to provide a first scan arch data of a dental arch with a plurality of fiducials inserted in edentulous areas of the dental arch, and wherein the system includes one or more processing unitsconfigured to determine, based on the first scan arch data a first virtual model of the dental arch that includes the plurality of fiducials, determine, based on the first scan arch data, positions of the plurality of fiducials relative to the first virtual model of the dental arch, determine, based on the positions of the plurality of fiducials, positions and orientations of a plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model, select, automatically, based on the position and the orientation of the plurality of virtual scan bodies, types of virtual scan bodies to be arranged in the plurality of fiducials in the first virtual model, and wherein the system further includes a display unit that is configured to display the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations of the virtual scan bodies in the plurality of fiducials.
[0041] After the plurality of scan bodies have been arranged inside the patients mouth the dentist may scan the jaw of the patient with an intraoral scanner. After the scanning the system may receive from a memory unit an electronical drawing (e.g. a CAD file) of the plurality of virtual scan bodies, and the system is further configured to compare the electronical drawing with the scanned plurality of scan bodies, and apply a difference map on a three-dimensional model of the scanned plurality of scan bodies and the plurality of virtual scan bodies mentioned in the electrical drawings. The difference map may include a difference score or a confidence score that is applied to the 3D model in the form of a color, multiple colors, or text / numbers.
[0042] The disclosure further relates to an intraoral scanning system configured to provide a plurality of intraoral scan images of a jaw with a plurality of scan bodies, and wherein the system includes one or more processing units configured to determine, based on the plurality of intraoral scan images, a three-dimensional model of the jaw, receive information on a geometry of the plurality of scan bodies, and improve the 3D model by comparing the scanned plurality of scan bodies with the information on the geometry of the plurality of scan bodies. The information on the geometry of the plurality of scan bodies may be stored in a memory unit of the system. The plurality of scan bodies may be arranged at specific positions determined by the system or at random positions butunder certain conditions, such as placement in different quadrants of a jaw (e.g. end-to-end molar)
[0043] BRIEF DESCRIPTION OF THE FIGURES
[0044] Aspects of the disclosure may be best understood from the following detailed description taken in conjunction with the accompanying figures. The figures are schematic and simplified for clarity, and they just show details to improve the understanding of the claims, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts. The individual features of each aspect may each be combined with any or all features of the other aspects. These and other aspects, features and / or technical effect will be apparent from and elucidated with reference to the illustrations described hereinafter in which:
[0045] FIG. 1 illustrates an example of a virtual model of a scanned dental arch and a full implant bridge,
[0046] FIG. 2 illustrates an example of a computer-implemented method,
[0047] FIG. 3 illustrates an example of a plurality of physical scan bodies to be arranged on a dental arch,
[0048] FIG. 4 illustrates an example of determining a physical scan body type and to determine a feedback signal
[0049] FIGS. 5A and 5B illustrate an example of determining a new position of fiducials, FIGS. 6 A and 6B illustrate an example of orienting a plurality of virtual scan bodies on a virtual model,
[0050] FIG. 7 illustrate an example of a segmentation algorithm, and
[0051] FIGS. 8A and 8B illustrate an example of how to generate a second feedback signal.DETAILED DESCRIPTION
[0052] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. Several aspects of the devices, systems, mediums, programs and methods are described by various blocks, functional units, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”).
[0053] Depending upon particular application, design constraints or other reasons, these elements may be implemented using electronic hardware, computer program, or any combination thereof.
[0054] The electronic hardware may include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. Computer program shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
[0055] A scanning for providing intra-oral scan data may be performed by a dental scanning system that may include an intraoral scanner, such as the TRIOS series scanners from 3 Shape A / S. The dental scanning system may include a wireless capability as provided by a wireless network unit. The intraoral scanner may employ a scanning principle such as triangulation-based scanning, confocal scanning, focus scanning, ultrasound scanning, x-ray scanning, stereo vision, structure from motion, optical coherent tomography OCT, or any other scanning principle. In an embodiment, the scanning device is capable of obtaining surface information by operated by projecting a pattern and translating a focus plane along an optical axis of the scanning device and capturing a plurality of 2D images at different focus plane positions such that each series of captured 2D imagescorresponding to each focus plane forms a stack of 2D images. The acquired 2D images are also referred to herein as raw 2D images, wherein raw in this context means that the images have not been subject to image processing. The focus plane position is preferably shifted along the optical axis of the scanning system, such that 2D images captured at several focus plane positions along the optical axis form said stack of 2D images (also referred to herein as a sub-scan) for a given view of the object, i.e. for a given arrangement of the scanning system relative to the object. After moving the scanning device relative to the object or imaging the object at a different view, a new stack of 2D images for that view may be captured. The focus plane position may be varied by means of at least one focus element, e.g., a moving focus lens. The scanning device is generally moved and angled relative to the dentition during a scanning session, such that at least some sets of sub-scans overlap at least partially, to enable reconstruction of the digital dental 3D model by stitching overlapping 3D subscans together in real-time and display the progress of the virtual 3D model on a display as feedback to the user. The result of stitching is the digital 3D representation of a surface larger than that which can be captured by a single sub-scan, i.e. which is larger than the field of view of the 3D scanning device. Stitching, also known as registration and fusion, works by identifying overlapping regions of 3D surface in various sub-scans and transforming sub-scans to a common coordinate system such that the overlapping regions match, finally yielding the digital 3D model. An Iterative Closest Point (ICP) algorithm may be used for this purpose. Another example of a scanning device is a triangulation scanner, where a time varying pattern is projected onto the plurality of dental objects and a sequence of images of the different pattern configurations are acquired by one or more cameras located at an angle relative to the projector unit.
[0056] The dental scanning system may be an intraoral scanning system. The scanning device may be an intraoral scanning device.
[0057] Color texture of the plurality of dental objects may be acquired by illuminating the object using different monochromatic colors such as individual red, green and blue colors or my illuminating the object using multi chromatic light such as white light. A 2D image may be acquired during a flash of white light.Generally, the process of obtaining surface information in real time of the plurality of dental objects to be scanned requires the scanning device to illuminate the surface and acquire high number of 2D images. Typically, a high-speed camera is used with a framerate of 300-20002D frames pr second dependent on the technology and 2D image resolution. The high amount of image data needed to be handled by the scanning device to eighter directly forward the raw image data stream to an external processing device or performing some image processing before transmitting the data to an external device or display. This process requires that multiple electronic components inside the scanner is operating with a high workload thus requiring a high demand of current.
[0058] The scanning device comprises one or more light projectors configured to generate an illumination pattern to be projected on a three-dimensional dental object during a scanning session. The light projector(s) preferably comprises a light source, a mask signal having a spatial pattern, and one or more lenses such as collimation lenses or projection lenses. The light source may be configured to generate light of a single wavelength or a combination of wavelengths (mono- or polychromatic). The combination of wavelengths may be produced by using a light source configured to produce light (such as white light) comprising different wavelengths. Alternatively, the light projector(s) may comprise multiple light sources such as LEDs individually producing light of different wavelengths (such as red, green, and blue) that may be combined to form light comprising the different wavelengths. Thus, the light produced by the light source may be defined by a wavelength defining a specific color, or a range of different wavelengths defining a combination of colors such as white light. In an embodiment, the scanning device comprises a light source configured for exciting fluorescent material of the teeth to obtain fluorescence data from the dental object. Such a light source may be configured to produce a narrow range of wavelengths. In another embodiment, the light from the light source is infrared (IR) light, which is capable of penetrating dental tissue. The light projector(s) may be DLP projectors using a micro mirror array for generating a time varying pattern, or a diffractive optical element (DOF), or back-lit mask signal projectors, wherein the light source is placed behind a mask signal having a spatial pattern, whereby the light projected on the surface of the dental object is patterned. The back-lit mask signal projector may comprise a collimation lens for collimating the light from the light source, said collimation lens beingplaced between the light source and the mask signal. The mask signal may have a checkerboard pattern, such that the generated illumination pattern is a checkerboard pattern. Alternatively, the mask signal may feature other patterns such as lines or dots, etc.
[0059] The scanning device preferably further comprises optical components for directing the light from the light source to the surface of the dental object. The specific arrangement of the optical components depends on whether the scanning device is a focus scanning apparatus, a scanning device using triangulation, or any other type of scanning device. A focus scanning apparatus is further described in EP 2442720 Bl by the same applicant, which is incorporated herein in its entirety.
[0060] The light reflected from the dental object in response to the illumination of the dental object is directed, using optical components of the scanning device, towards the image sensor(s). The image sensor(s) are configured to generate a plurality of images based on the incoming light received from the illuminated dental object. The image sensor unit may be a high-speed image sensor such as an image sensor configured for acquiring images with exposures of less than 1 / 1000 second or frame rates in excess of 250 frames pr. second (fps). As an example, the image sensor may be a rolling shutter (CCD) or global shutter sensor (CMOS). The image sensor(s) may be a monochrome sensor including a color filter array such as a Bayer filter and / or additional filters that may be configured to substantially remove one or more color components from the reflected light and retain only the other non-removed components prior to conversion of the reflected light into an electrical signal. For example, such additional filters may be used to remove a certain part of a white light spectrum, such as a blue component, and retain only red and green components from a signal generated in response to exciting fluorescent material of the teeth.
[0061] The network unit may be configured to connect the dental scanning system to a network comprising a plurality of network elements including at least one network element configured to receive the processed data. The network unit may include a wireless network unit or a wired network unit. The wireless network unit is configured to wirelessly connect the dental scanning system to the network comprising the plurality of network elementsincluding the at least one network element configured to receive the processed data. The wired network unit is configured to establish a wired connection between the dental scanning system and the network comprising the plurality of network elements including the at least one network element configured to receive the processed data.
[0062] The dental scanning system preferably further comprises a processor configured to generate scan data (such as extra-oral scan data and / or intra-oral scan data) by processing the two-dimensional (2D) images acquired by the scanning device. The processor may be part of the scanning device. As an example, the processor may comprise a Field-programmable gate array (FPGA) and / or an Advanced RISC Machines (ARM) processor located on the scanning device. The scan data comprises information relating to the three-dimensional dental object. The scan data may comprise any of 2D images, 3D point clouds, depth data, texture data, intensity data, color data, and / or combinations thereof. As an example, the scan data may comprise one or more point clouds, wherein each point cloud comprises a set of 3D points describing the three-dimensional dental object. As another example, the scan data may comprise images, each image comprising image data e.g. described by image coordinates and a timestamp (x, y, t), wherein depth information can be inferred from the timestamp. The image sensor(s) of the scanning device may acquire a plurality of raw 2D images of the dental object in response to illuminating said object using the one or more light projectors. The plurality of raw 2D images may also be referred to herein as a stack of 2D images. The 2D images may subsequently be provided as input to the processor, which processes the 2D images to generate scan data. The processing of the 2D images may comprise the step of determining which part of each of the 2D images are in focus in order to deduce / generate depth information from the images. The internal depth information may be used to generate 3D point clouds comprising a set of 3D points in space, e.g., described by cartesian coordinates (x, y, z). The 3D point clouds may be generated by the processor or by another processing unit. Each 2D / 3D point may furthermore comprise a timestamp that indicates when the 2D / 3D point was recorded, i.e., from which image in the stack of 2D images the point originates. The timestamp is correlated with the z-coordinate of the 3D points, i.e., the z-coordinate may be inferred from the timestamp. Accordingly, the output of the processor is the scan data, and the scan data may comprise image data and / or depth data, e.g. described by image coordinates anda timestamp (x, y, t) or alternatively described as (x, y, z). The scanning device may be configured to transmit other types of data in addition to the scan data. Examples of data include 3D information, texture information such as infra-red (IR) images, fluorescence images, reflectance color images, x-ray images, and / or combinations thereof.
[0063] FIG. 1 illustrates an example of a virtual model 3 of a scanned dental arch which includes a plurality of fiducials (2A - 2F), in this example, abutments configured to receive a full implant bridge 10. It is important to know the exact position of the plurality of fiducials such that, in this example, the full implant bridge 10 can be designed optimally to a patient, such that no inconvenience is experienced by the user while wearing the full implant bridge 10. The plurality of fiducials (2A - 2F) could be configured to receive single crowns designed for the patient or a dental bridge that includes multiple designed crowns / teeth.
[0064] FIG. 2 illustrates an example of a computer-implemented method 1 that is configured for arranging a plurality of physical scan bodies relative to a plurality of fiducials inserted into a dental arch of a patients’ mouth. The method 1 comprising providing 11 A a first scan arch data of a dental arch 3 with a plurality of fiducials (2A - 2F) inserted in edentulous areas of the dental arch 3. The first scan arch data may be provided by an intraoral scanner 7 that may be configured to provide three-dimensional data of the dental arch based on a focus scanning principle or a triangulation scanning principle. The first scan arch data (and a second scan arch data) may include either two-dimensional scan data or three-dimensional scan data which includes geometrical data of the dental arch. In this example, the first scan arch data includes three-dimensional data. The computer-implemented method 1 further includes determining, based on the first scan arch data, a first virtual model 3 A of the dental arch 3 that includes the plurality of fiducials (2A - 2F). The first virtual model 3 A is a three-dimensional virtual model of the dental arch. The computer-implemented method 1 includes determining 1 IB, based on the first scan arch data, positions of the plurality of fiducials, and in this example, the positions of the plurality of fiducials are determined based on a distance and a relative angle between the plurality of fiducials. In this specific example, the distance and relative angle are determined between neighbouring fiducials of the plurality of fiducials. Based on the positions of the pluralityof fiducials, positions and orientations of a plurality of virtual scan bodies (4A - 4F) relative to the plurality of fiducials in the first virtual model is determined 11C. The positions of the plurality of fiducials may be arranged according to a two-dimensional or a three-dimensional coordinate system in which an optimal orientation of each of the plurality of virtual scan bodies is determined. The optimal orientation is determined such that a distal end 9 of the plurality of virtual scan bodies (4A-4F) form a curve that partly or fully resembles the curved shape of the dental arch 3 A which the plurality of virtual scan bodies (4A - 4F) is applied to. In one example, the plurality of virtual scan bodies should not overlap with each other, and thereby, the computer-implemented method selects, automatically, based on the position and the orientation of the plurality of virtual scan bodies, types of virtual scan bodies to be arranged on the plurality of fiducials in the first virtual model such that none of the scan bodies overlap.
[0065] The displaying which is seen in FIG. 2 11C of the first virtual model 3 A with the selected type of virtual scan bodies (4A - 4F) arranged according to the positions and orientation relative to the plurality of fiducials (2A - 2F) assists the user in the selection of a plurality of physical scan bodies (5A,5B, 5C) to be inserted into the patient’s mouth, see FIG. 3, 14 A, and, how to position and orientate each of the plurality of physical scan bodies (5 A -5F), see FIG. 3, 14B. The selection of the plurality of physical scan bodies may be manually done by the user or done by a robotic arm that receives instructions from one or more processing units configured to process the computer-implemented method 1. In the example illustrated in FIG. 3, the first virtual model with the plurality of virtual scan bodies is displayed on the displaying unit 15, and while the user is connecting the physical scan bodies (5A - 5F) to the respective fiducials (2A - 2F) the user is able to see how each of the physical scan bodies (5 A - 5F) should be placed and orientated in relation to the dental arch 3 but also in relation to the other physical scan bodies (5A - 5F). The manually selected plurality of physical scan bodies corresponds to the selected types of virtual scan bodies (4A-4F) that are seen on the displaying unit 15. Furthermore, the user can then arrange, manually and according to the positions and orientation of the plurality of virtual scan bodies (4A - 4F), the selected plurality of physical scan bodies (5 A - 5F) onto the plurality of fiducials in the dental arch 3.After the user has selected and arranged the plurality of physical scan bodies (5 A-5F) onto the plurality of fiducials in the dental arch 3, the dental arch 3 is scanned, by an intraoral scanner 7, providing a second scan arch data of the dental arch with the selected plurality of physical scan bodies (5A-5F) arranged onto the plurality of fiducials. Based on the second scan arch data, a second virtual model 3B of the dental arch is determined. The type of the plurality of physical scan bodies may be determined automatically or manually and based on the types of the plurality of physical scan bodies, the position and orientation of the plurality of physical scan bodies, new positions of the plurality of fiducials can be determined. In the example illustrated in FIG. 4, the type of a physical scan body is determined automatically, by first identifying 40A the plurality of physical scan bodies (5A-5F), and then determining 40B, the type of each of the plurality of physical scan bodies. Then, the determined 40B types are then compared 40C with the plurality of virtual scan bodies of corresponding fiducials such that a warning would appear to the user if a match were not presented in the comparing of the physical (5 A-5F) and virtual scan bodies (4A-4F). In this present example, the warning is a feedback signal (40D’, 40D”). The computer-implemented method generating a first feedback signal, based on the second scan arch data, on whether the manually selected plurality of physical scan bodies (5 A - 5F) matches the plurality of virtual scan (4A - 4F) bodies for the corresponding plurality of fiducials. Thereby, the user will be notified during the scanning of the plurality of physical scan bodies or just after the scanning, via the first feedback signal on whether the user has selected a correct physical scan body for a certain fiducial. If the selected physical scan body is not correct, then the user would be able to remove and select a new physical scan body and perform the scanning of the plurality of physical scan bodies again.
[0066] FIGS. 5A and 5B illustrate an example of determining new positions of the plurality of fiducials by first determining the type of the plurality of physical scan bodies in the second virtual model 3B, and determining, based on an arrangement of the plurality of physical scan bodies in the second virtual model 3B and the determined type of plurality of physical scan bodies, new positions 22 of the plurality of fiducials. The previouspositions 22 of the plurality of fiducials may appear along with the new positions 22 in the first 3 A or the second model 3B, with / without the dental arch.
[0067] In the second virtual model 3B the scanned plurality of physical scan bodies is aligned relative to the scanned plurality of fiducials by identifying the plurality of physical scan bodies (5 A-5F) in the second virtual model 4B via a segmentation algorithm. The identifying of the plurality of physical scan bodes (5A-5F) may be provided by determining, based on the second scan arch data, a shape of at least a geometrical part of each of the plurality of physical scan bodies, comparing the shape of at least the geometrical part with a known shape of a reference geometrical part of a reference scan body, determining a complete shape of each of the plurality of physical scan bodies according to a shape of the reference scan body where a match shape between the geometrical part and the reference geometrical part is obtained, and wherein the segmentation algorithm is configured to segment each of the plurality of physical scan bodies based on the determined shape of the complete scan body.
[0068] In FIG. 5 A the second virtual model 3B includes both the dental arch 3 and the plurality of physical scan bodies (5 A-5F), however, in FIG. 5B the second virtual model 3B includes only the plurality of physical scan bodies (5 A-5F).
[0069] FIGS. 6A and 6B illustrates different example on how the types and orientations of the plurality of virtual scan bodies (4A - 4F) are determined. The determined orientation of the plurality of virtual scan bodies (4 A - 4F) includes determining line axes 17 of the plurality of virtual scan bodies (4A-4F) relative to the positions of the plurality of fiducials, determining an orientation of the line axes 17, such that at least a group of the line axes 17 intersect at an intersection point 13, and determining, based on the orientation of the line axes 17, the types of virtual scan bodies (4A-4F) to be arranged at the plurality of fiducials. In FIG. 6A, the group of lines axes includes two lines axes (17A, 17B) that intersections at a given point 13. In the present example, the group of lines axes (17A, 17B) originate from two neighbouring fiducials (2C,2D) which are central arranged, such that if an even number of fiducials (2A - 2F) are arranged on the dental arch, then equal number of fiducials (2A, 2B, 2E, 2F)are arranged on both sidesof the two fiducials (2C,2D). Each of the line axes 17 corresponds to a virtual scan body 4. By optimizing the orientation of the grouped line axes (17A, 17B), such that an intersection point 13 is obtained between the two line axes (17A,17B), then the remaining plurality of virtual scan bodies (4A,4B,4E, 4F) are arranged such that a certain distance (12A-12B) is obtained between the virtual scan bodies (4A - 4F). Which means that only two neighbouring virtual scan bodies are oriented such the respective lines axes (17A,17B) have an intersection point. In FIG. 6A, the orientation of all virtual scan bodies (4A - 4F) are determined such that all lines axes of the virtual scan bodies (4A-4F) have at least one intersection point 13. In this specific example, two intersection points (13A, 13B) are obtained because of the distance between the fiducials (2A- 2F).
[0070] In yet another example, the determined orientation of the plurality of virtual scan bodies (4A - 4F) includes determining line axes 17of the plurality of virtual scan bodies (4A -4F) relative to the positions of the plurality of fiducials (2A - 2F), determining an orientation of the line axes 17, such that at least a group of the line axes intersect at an intersection point 13, and determining, based on the orientation of the line axes 17, the types of virtual scan bodies to be arranged on the plurality of fiducials (2A - 2F). The positions of the plurality of fiducials (2A - 2F) is arranged according to a two-dimensional or a three-dimensional coordinate system in which an optimal orientation of each of the plurality of virtual scan bodies (4A - 4F) is determined based on the orientation of the line axes. For example, each of plurality of fiducials may be represented by points (Pl, P2, P3, P4, P5, P6) along the dental arch which have a distance between that can be determined by:
[0071] -i=|Ei+i— P[ \ .
[0072] The dental arch with the six points (Pl, P2, P3, P4, P5, P6) that represent virtual fiducials is defined in a two-dimensional coordinate system, such that each of the points has a position (x, y) determined by the distance di between the four points and a relative angle between successive points (Pl, P2, P3, P4, P5, P6). A line axis 17 may originate from each of the points (Pl, P2, P3, P4, P5, P6) at an angle towards a meeting point Pm=
[0073]
[0074] . The equation of the line axis may be determined by following equation:(x - Xi)2+ (y - y,-)2= L2.
[0075] The line axis Li should point towards Pm, and the above equation can be written parametrically:
[0076] <
[0077]
[0078] is the direction of the line axis. To ensure that all line axes of the plurality of fiducials, i.e. the points (Pl, P2, P3, P4, P5, P6), meet at Pm then following equation should be solved:
[0079] xm= Xi + Licos (ai),ym= yt+ LiSin (ai) Vi e {1,2, 3, 4}.
[0080] Since the line axes Li are discrete, the problem can be solved using brute-force search or optimization techniques, such as minimizing the sum of squared distances of the line axes’ endpoints to a common point.
[0081] To determine the Best Length Combination enumerate all possible combinations of line axes, and for each combination, solve the above equations for Pm. Check the error by computing the distance between the estimated intersection point and endpoints of the line axes. Then, select the optimal solution that minimizes the total error.
[0082] FIG. 7 illustrates an example of the segmentation algorithm 70 that is configured to distinguish between a tooth, gingival, moving objects, fiducials, and a physical scan body. The algorithm 70 includes following steps: determining 70A a shape of a model object based on 3D geometrical data, provided by the second scan arch data, comparing 70B the shape with a reference shape, determining 70C a complete shape of the object, and based on the complete shape of the object, the algorithm 70 is configured to distinguish 70D between a tooth, gingival, moving objects, fiducials, and a physical scan body. The segmentation algorithm 70 uses vectors perpendicular to each surface identified in the 3D geometrical data, or a single vector, perpendicular to the whole model object, and one point in the middle of each model object or two points on the distal and mesial sides of the model object. A preferred version of the segmentation algorithm 70 is based on using a 3D shortest path algorithm, preferably capable of handling negative weights, for example theBellman-Ford algorithm. The algorithm 70 is preferably applied on a 3D matrix with elements representing curvature of the surface of the model object. Segmentation algorithm can be based on color and / or 3D geometrical data of the second scan arch data. Segmentation is at least partly provided by means of a computer implemented algorithm, such as a shortest-path algorithm applied on a 3D matrix representing curvature of the tooth surface. Segmentation may further at least partly be based on texture information in the 3D representations.
[0083] It is important that when scanning the plurality of physical scan bodies (5A - 5F) at least two neighbouring physical scan bodies (5 A - 5F) of the plurality of physical scan bodies (5 A - 5F) have to be within a scanning window 30A of the intraoral scanner 7, such that image frames of the scan arch data can be stitched together to form a two / three-dimensional model of the plurality of physical scan bodies with / without the dental. During scanning of the plurality of physical scan bodies (5A - 5F) a second feedback signal is generated if the scanning window (30 A, 3 OB) does not include two or more of the plurality of physical scan bodies. For example, in the example where the scanning window 30A does only include a single physical scan body, see FIGS. 8 A and 8B, then the second feedback signal is generated informing the user to change position of the physical scan bodies in vicinity of the scanning window 30 A. In the other example where the scanning window 30B does include two physical scan bodies then no feedback signal is generated.
[0084] ITEMS
[0085] 1. A computer-implemented method for arranging a plurality of physical scan bodies relative to a plurality of fiducials inserted into a dental arch of a patient’s mouth, the method comprising:
[0086] • providing a first scan arch data of a dental arch with a plurality of fiducials inserted in edentulous areas of the dental arch,• determining, based on the first scan arch data a first virtual model of the dental arch that includes the plurality of fiducials,
[0087] • determining, based on the first scan arch data, positions of the plurality of fiducials relative to the first virtual model of the dental arch,
[0088] • determining, based on the positions of the plurality of fiducials, positions and orientations of a plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model,
[0089] • selecting, automatically, based on the position and the orientation of the plurality of virtual scan bodies, types of virtual scan bodies to be arranged on the plurality of fiducials in the first virtual model, and
[0090] • displaying the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations relative to the plurality of fiducials.
[0091] computer-implemented method according to item 1, comprising
[0092] • selecting, manually, a plurality of physical scan bodies that corresponds to the selected types of virtual scan bodies,
[0093] • arranging, manually and according to the positions and the orientations of the plurality of virtual scan bodies, the selected plurality of physical scan bodies onto the plurality of fiducials in the dental arch,
[0094] • scanning the dental arch with the selected plurality of physical scan bodies arranged onto the plurality of fiducials in the dental arch,
[0095] • providing a second scan arch data of the dental arch with the selected plurality of physical scan bodies arranged onto the plurality of fiducials,
[0096] • determining, based on the second scan arch data, a second virtual model of the dental arch that includes the selected plurality of physical scan bodies arranged onto the plurality of fiducials, and
[0097] • displaying the second virtual model that includes the plurality of physical scan bodies.
[0098] he computer-implemented method according to item 2, comprising:• determining, based on the plurality of physical scan bodies in the second virtual model, new positions of the plurality of fiducials relative to the dental arch, and • displaying the plurality of fiducials at the new positions in the second virtual model or in the first virtual model.
[0099] 4. The computer-implemented method according to item 2 or 3, comprising determining the type of the plurality of physical scan bodies, and determining, based on an arrangement of the plurality of physical scan bodies and the determined type of plurality of physical scan bodies, new positions of the plurality of fiducials.
[0100] 5. The computer-implemented method according to any of the previous items, wherein the determining of the positions and orientations of the plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model includes a curved shape arrangement between distal ends of the plurality of virtual scan bodies, and wherein the distal end of each of the plurality of virtual scan bodies is distantly arranged to the plurality of fiducials.
[0101] 6. The computer-implement method according to item 5, wherein a first radius-curve of the curved shaped arrangement is less than a second radius-curve of the dental arch in the first virtual model.
[0102] 7. The computer-implemented method according to any of the previous items, wherein the determined orientation of the plurality of virtual scan bodies includes:
[0103] • determining line axes of the plurality of virtual scan bodies relative to the positions of the plurality of fiducials,
[0104] • determining an orientation of the line axes, such that at least a group of the line axes intersect at an intersection point, and
[0105] • determining, based on the orientation of the line axes, the types of virtual scan bodies to be arranged on the plurality of fiducials.8. The computer-implemented method according to any of the previous items, wherein the types of virtual scan bodies include multiple virtual scan bodies with different sizes or lengths.
[0106] 9. The computer-implemented method according to item 2, wherein the aligning of the scanned plurality of physical scan bodies relative to the scanned plurality of fiducials in the second virtual model comprising identifying the plurality of physical scan bodies in the second virtual model by a segmentation algorithm.
[0107] 10. The computer-implemented method according to item 9, comprising identifying the plurality of physical scan bodies by:
[0108] • determining, based on the second scan arch data, a shape of at least a geometrical part of each of the plurality of physical scan bodies,
[0109] • comparing the shape of at least the geometrical part with a known shape of a reference geometrical part of a reference scan body,
[0110] • determining a complete shape of each of the plurality of physical scan bodies according to a shape of the reference scan body where a match shape between the geometrical part and the reference geometrical part is obtained, and wherein the segmentation algorithm is configured to segment each of the plurality of physical scan bodies based on the determined shape of the complete scan body.
[0111] 11. The computer-implemented method according to any of the previous items, wherein the determining of the positions of the plurality of fiducials in the first virtual model is provided by a segmentation algorithm.
[0112] 12. The computer-implemented method according to item 11, initiating an implant design workflow based on detection of the plurality of fiducials via the segmentation algorithm.
[0113] 13. The computer-implemented method according to any of the previous items, comprising generating a first feedback signal, based on the second scan arch data,whether the manually selected plurality of physical scan bodies matches the plurality of virtual scan bodies for the corresponding plurality of fiducials.
[0114] 14. The computer-implemented method according to item 9, comprising:
[0115] • determining, based on the second scan arch data and the segmentation algorithm, type of the plurality of physical scan bodies that are arranged relative to the plurality of fiducials in the second virtual model,
[0116] • comparing for each of the plurality of fiducials, the determined type of a physical scan body of the plurality of physical scan bodies with a virtual scan body of the plurality of virtual scan bodies for a corresponding fiducial of the plurality of fiducials, and
[0117] • generating a first feedback signal to a user based on the comparing between the plurality of physical scan bodies with the plurality of virtual scan bodies for each of the plurality of fiducials.
[0118] 15. The computer-implemented method according to any of the previous items, comprising generating a second feedback signal on whether two or more of the plurality of physical scan bodies are detected in a single scan frame of the second scan arch data.
Claims
1. 28CLAIMS1. A computer-implemented method for arranging a plurality of physical scan bodies relative to a plurality of fiducials inserted into a dental arch of a patient’s mouth, the method comprising:• providing, by an intraoral scanner, a first scan arch data of a dental arch with a plurality of fiducials inserted in edentulous areas of the dental arch,• determining, based on the first scan arch data a first virtual model of the dental arch that includes the plurality of fiducials,• determining, based on the first scan arch data, positions of the plurality of fiducials relative to the first virtual model of the dental arch,• determining, based on the positions of the plurality of fiducials, positions and orientations of a plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model,• selecting, automatically, based on the position and the orientation of the plurality of virtual scan bodies, types of virtual scan bodies to be arranged in the plurality of fiducials in the first virtual model, and• displaying the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations of the virtual scan bodies in the plurality of fiducials.
2. A computer-implemented method according to claim 1, comprising• selecting, manually, a plurality of physical scan bodies that corresponds to the selected types of virtual scan bodies,• arranging, manually and according to the positions and the orientations of the plurality of virtual scan bodies, the selected plurality of physical scan bodies onto the plurality of fiducials in the dental arch,• scanning the dental arch with the selected plurality of physical scan bodies arranged onto the plurality of fiducials in the dental arch,• providing a second scan arch data of the dental arch with the selected plurality of physical scan bodies arranged onto the plurality of fiducials,• determining, based on the second scan arch data, a second virtual model of the dental arch that includes the selected plurality of physical scan bodies arranged onto the plurality of fiducials, and• displaying the second virtual model that includes the plurality of physical scan bodies.
3. The computer-implemented method according to claim 2, comprising:• determining, based on the plurality of physical scan bodies in the second virtual model, new positions of the plurality of fiducials relative to the dental arch, and • displaying the plurality of fiducials at the new positions in the second virtual model or in the first virtual model.
4. The computer-implemented method according to claim 2 or 3, comprising determining the type of the plurality of physical scan bodies, and determining, based on an arrangement of the plurality of physical scan bodies and the determined type of plurality of physical scan bodies, new positions of the plurality of fiducials.
5. The computer-implemented method according to any of the previous claims, wherein the determining of the positions and orientations of the plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model includes a curved shape arrangement between distal ends of the plurality of virtual scan bodies, and wherein the distal end of each of the plurality of virtual scan bodies is distantly arranged to the plurality of fiducials.
6. The computer-implement method according to claim 5, wherein a first radius-curve of the curved shaped arrangement is less than a second radius-curve of the dental arch in the first virtual model.
7. The computer-implemented method according to any of the previous claims, wherein the determined orientation of the plurality of virtual scan bodies includes:• determining line axes of the plurality of virtual scan bodies relative to the positions of the plurality of fiducials,• determining an orientation of the line axes, such that at least a group of the line axes intersect at an intersection point, and• determining, based on the orientation of the line axes, the types of virtual scan bodies to be arranged on the plurality of fiducials.
8. The computer-implemented method according to any of the previous claims, wherein the types of virtual scan bodies include multiple virtual scan bodies with different sizes or lengths.
9. The computer-implemented method according to claim 2, wherein the aligning of the scanned plurality of physical scan bodies relative to the scanned plurality of fiducials in the second virtual model comprising identifying the plurality of physical scan bodies in the second virtual model by a segmentation algorithm.
10. The computer-implemented method according to claim 9, comprising identifying the plurality of physical scan bodies by:• determining, based on the second scan arch data, a shape of at least a geometrical part of each of the plurality of physical scan bodies,• comparing the shape of at least the geometrical part with a known shape of a reference geometrical part of a reference scan body,• determining a complete shape of each of the plurality of physical scan bodies according to a shape of the reference scan body where a match shape between the geometrical part and the reference geometrical part is obtained, and wherein the segmentation algorithm is configured to segment each of the plurality of physical scan bodies based on the determined shape of the complete scan body.
11. The computer-implemented method according to any of the previous claims, wherein the determining of the positions of the plurality of fiducials in the first virtual model is provided by a segmentation algorithm.
12. The computer-implemented method according to claim 11, initiating an implant design workflow based on detection of the plurality of fiducials via the segmentation algorithm.
13. The computer-implemented method according to any of the previous claims, comprising generating a first feedback signal, based on the second scan arch data, whether the manually selected plurality of physical scan bodies matches the plurality of virtual scan bodies for the corresponding plurality of fiducials.
14. The computer-implemented method according to claim 9, comprising:• determining, based on the second scan arch data and the segmentation algorithm, type of the plurality of physical scan bodies that are arranged relative to the plurality of fiducials in the second virtual model,• comparing for each of the plurality of fiducials, the determined type of a physical scan body of the plurality of physical scan bodies with a virtual scan body of the plurality of virtual scan bodies for a corresponding fiducial of the plurality of fiducials, and• generating a first feedback signal to a user based on the comparing between the plurality of physical scan bodies with the plurality of virtual scan bodies for each of the plurality of fiducials.
15. An intraoral scanning system configured to provide a first scan arch data of a dental arch with a plurality of fiducials inserted in edentulous areas of the dental arch, and wherein the system includes one or more processing units configured to:• determine, based on the first scan arch data a first virtual model of the dental arch that includes the plurality of fiducials,• determine, based on the first scan arch data, positions of the plurality of fiducials relative to the first virtual model of the dental arch,• determine, based on the positions of the plurality of fiducials, positions and orientations of a plurality of virtual scan bodies relative to the plurality of fiducials in the first virtual model,• select, automatically, based on the position and the orientation of the plurality of virtual scan bodies, types of virtual scan bodies to be arranged in the plurality of fiducials in the first virtual model, andwherein the system further includes a display unit that is configured to display the first virtual model that includes the selected types of virtual scan bodies arranged according to the positions and the orientations of the virtual scan bodies in the plurality of fiducials.