Oral scanner with tomography function and oral tomography method using the same

Abstract

Disclosed is an oral cavity scanner having a tomography function and an oral cavity tomography method using the same. The oral cavity scanner having a tomography function includes a shape measurement light projector that irradiates shape measurement light for obtaining a shape image of an oral cavity structure; a shape measurement camera that detects reflected light formed by reflection of the shape measurement light on a surface of the oral cavity structure to obtain a surface shape image of the oral cavity structure; an OCT main body that transmits tomographic light to the oral cavity structure and detects reflected light reflected inside the oral cavity structure to obtain an internal cross-sectional image of the oral cavity structure; an OCT scanning probe that irradiates tomographic light emitted from the OCT main body to a desired position of the oral cavity structure and transmits reflected light reflected from the oral cavity structure to the OCT main body; and a beam splitter that overlaps optical paths of the shape measurement light irradiated by the shape measurement light projector and the tomographic light irradiated by the OCT scanning probe.

Description

Technical Field

[0001] This invention relates to an oral scanner with tomographic imaging capabilities, and more specifically, to an oral scanner with tomographic imaging capabilities capable of using shape information inside the oral cavity to define the tomographic imaging region, and a method for tomographic imaging of the oral cavity using the same. Background Technology

[0002] Typically, in dental hospitals and other facilities, the shape of the teeth or tissues inside a patient's mouth is examined to diagnose the patient's oral condition or to create restorations. Previously, methods for obtaining the shape of the teeth and tissues inside the mouth included impressions using alginate or other impression materials, or methods involving external X-ray exposure to obtain two-dimensional or three-dimensional shapes of the oral structure. However, these methods struggle to obtain accurate three-dimensional shapes of the oral cavity.

[0003] Recently, optical oral scanners have been used to measure the shape and condition of the oral cavity by scanning and photographing the morphology inside the patient's oral cavity in three dimensions without physical contact. Figure 1 This is a diagram illustrating the principles of oral cavity shape imaging using a typical oral scanner. Figure 1 As shown, a typical oral scanner includes: a projector 12, which includes a light source that illuminates measuring light onto oral structures S such as teeth; and a camera 14, which includes an image sensor that detects the light reflected from the oral structures S to obtain the surface shape of the oral structures S. Measuring light (e.g., visible light) illuminating the oral structures S inside the oral cavity from the light source of the projector 12 is used, and the image sensor of the camera 14 detects the light reflected from the oral structures S to obtain surface shape information of the oral structures S. At this time, the two-dimensional image of the oral structures S detected by the camera 14 can be converted into a three-dimensional image using methods such as triangulation. That is, a typical oral scanner illuminates the desired location inside the oral cavity with measuring light and detects the reflected light generated by the reflection of the measuring light on the oral structures to obtain only the surface shape information of oral structures such as teeth.

[0004] When using a conventional oral scanner, the internal condition of the oral structure S cannot be examined. Therefore, the method of obtaining internal tomographic images of the oral structure S using an optical coherence tomography (OCT) device is known (see Korean Patent Application No. 10-2020-0175365). Figure 2 This diagram illustrates a method for obtaining internal tomographic images of an oral cavity structure S using a conventional optical interferometry (OCT) scanner. (See diagram for example.) Figure 2As shown, a typical optical interferometry (OCT) scanner includes: an OCT body 22 that transmits measurement light (e.g., near-infrared light) to an oral structure S such as a tooth, and detects reflected light (scattered light) within the oral structure S and at each section, in order to obtain...

[0005] The internal cross-sectional image of the oral cavity structure S is obtained; and an OCT scan probe 24 is used, which 5 illuminates the desired location of the oral cavity structure S with the measurement light emitted by the OCT body 22, and will...

[0006] The reflected light from the oral structure S is transmitted to the OCT body 22. The OCT body 22 is a typical device for obtaining tomographic information of the interior of an object by utilizing the coherence properties of measurement light. The OCT scanning probe 24 may include: a collimator 24a, which focuses the measurement light and the reflected light; a mirror 24b, which reflects the focused measurement light to the desired imaging position of the oral structure S and transmits the reflected light from the oral structure S to the collimator 24a; and an objective lens 24c, which focuses the measurement light reflected by the mirror 24b to the desired imaging position of the oral structure S. The mirror 24b may be a MEMS mirror (micro electromechanical system mirror) that allows the imaging position of the oral structure S to be scanned sequentially by adjusting the reflection angle of the measurement light.

[0007] Because such optical interferometric tomography (OCT) scanners obtain tomographic images of the object being measured based on a single-line scan in the depth direction (z5 direction) and a lateral direction (x or y direction),

[0008] Therefore, it is not easy to obtain a tomographic image of the entire object being measured. In addition, the OCT scanning probe 24 is a hand-held probe, and when using it to obtain images of intraoral structures, the optical interference tomography area is small, making it difficult to obtain tomographic images of the desired location.

[0009] [Existing Technical Documents]

[0010] 0 1. Korean Patent Registration No. 10-2088951

[0011] 2. Korean Patent Registration No. 10-1449168

[0012] 3. International Patent Publication WO2019 / 005055

[0013] 4. International Patent Publication WO2019 / 002616

[0014] 5. International Patent Publication WO2017 / 176300

[0015] 5 6. European Patent Publication EP2060227 A1

[0016] 7. Sensors (Basel) July 2013; 13(7): 8928-8949, Dental Optical Coherence Tomography (https: / / www.ncbi.nlm.nih.gov / pmc / articles / PMC3758630)

[0017] 8. J. Clinical Medicine 2019, 8(6), 785. Comparative study of methods for evaluating the marginal and internal fit of fixed dental prostheses (https: / / www.mdpi.com / 2077-0383 / 8 / 6 / 785)

[0018] 9. Applied Microbiology Letters, Vol. 54, No. 6, June 2012, 537-542, Quantification of Dental Biofilm Growth Using Cross-Polarized Optical Coherence Tomography (https: / / sfamjournals.onlinelibrary.wiley.com / doi / full / 10.1111 / j.1472-765X.2012.03243.x)

[0019] 10. Journal of Biophotonics, Vol. 11, No. 12, December 2018, e201800242, Non-invasive imaging and measurement of gingiva using optical coherence tomography: In vivo studies (https: / / onlinelibrary.wiley.com / doi / full / 10.1002 / jbio.201800242) Summary of the Invention

[0020] Technical issues

[0021] One object of the present invention is to provide an oral scanner with tomographic function that can acquire tomographic images of the oral cavity by combining with an optical interferometry (OCT) device, and a method for tomographic imaging of the oral cavity using the same.

[0022] Another object of the present invention is to provide an oral scanner with tomographic function that can effectively acquire tomographic images of only desired locations inside the oral cavity, and a method for tomographic imaging of the oral cavity using the same.

[0023] Technical solution

[0024] To achieve the above objectives, the present invention provides an oral scanner with tomographic imaging capabilities, comprising: a shape measurement light projector 12, which illuminates shape measurement light for obtaining shape images of oral structures; a shape measurement camera 14, which detects reflected light formed by the shape measurement light reflected from the surface of the oral structure to obtain a surface shape image of the oral structure; an OCT body 22, which transmits tomographic light to the oral structure and detects reflected light reflected from the interior of the oral structure to obtain an internal cross-sectional image of the oral structure; an OCT scanning probe 24, which illuminates the desired location of the oral structure with the tomographic light emitted by the OCT body 22 and transmits the reflected light reflected from the oral structure to the OCT body 22; and a beam splitter 30, which overlaps the optical paths of the shape measurement light illuminated by the shape measurement light projector 12 and the tomographic light illuminated by the OCT scanning probe 24.

[0025] Furthermore, the present invention provides a method for tomographic imaging of the oral cavity, comprising: a step of sequentially illuminating a shape measurement light onto an oral cavity structure and detecting reflected light formed by the reflection of the shape measurement light on the surface of the oral cavity structure to obtain an overall image T of the oral cavity structure; a step of setting the position of a region of interest (ROI) for tomographic imaging of the overall image T of the oral cavity structure; and a step of transmitting tomographic light along the set region of interest (ROI) and detecting reflected light reflected inside the region of interest (ROI) to obtain an internal cross-sectional image of the region of interest (ROI).

[0026] The effects of the invention

[0027] According to the oral scanner with tomography function of the present invention and the oral cavity tomography method using the same, tomographic images of the oral cavity can be acquired by combining with an optical interferometry (OCT) device. In particular, tomographic images of only desired locations inside the oral cavity can be effectively acquired. Attached Figure Description

[0028] Figure 1 This is a diagram illustrating the principles of oral cavity shape imaging using a typical oral scanner.

[0029] Figure 2 This figure illustrates a method for obtaining internal tomographic images of oral structures using a conventional optical interferometry (OCT) scanner.

[0030] Figure 3 This is a diagram illustrating the structure of an oral scanner with tomographic imaging function according to an embodiment of the present invention.

[0031] Figures 4 to 7 This is a diagram illustrating a method for taking a tomographic image of the oral cavity using an oral scanner with tomographic imaging capabilities according to the present invention.

[0032] Figure 8 This is a flowchart illustrating an embodiment of the oral cavity tomography method of the present invention.

[0033] Figure 9 This is a diagram illustrating an example of performing tomography on a specific region of interest in the oral cavity according to the present invention. Detailed Implementation

[0034] The invention will now be described in detail with reference to the accompanying drawings. In the drawings, elements that perform the same or similar functions as in the past are given the same reference numerals.

[0035] Figure 3 This is a diagram illustrating the structure of an oral scanner with tomographic imaging capability according to an embodiment of the present invention. Figure 3 As shown, the oral scanner with tomography function of the present invention includes a shape measurement light projector 12, a shape measurement camera 14, an OCT (Optical Coherence Tomography) body 22, an OCT scanning probe 24, and a beam splitter 30. The shape measurement light projector 12 illuminates shape measurement light for obtaining shape images of oral structures S such as teeth. As the shape measurement light, any measurement light capable of obtaining shape images of oral structures S can be used without limitation; preferably, visible light, such as visible light with a wavelength of 400 to 700 nm, can be used. The shape measurement camera 14 is a device for detecting reflected light formed by the shape measurement light reflected from the surface of the oral structure S to obtain a surface shape image of the oral structure S, and includes a conventional image sensor. In operation, the shape measurement light is output from the shape measurement light projector 12, and after passing through the beam splitter 30, the output shape measurement light is illuminated onto the oral structure S. The reflected light reflected from the oral structure S is detected by the shape measurement camera 14 to obtain a surface shape image of the oral structure S. At this point, the two-dimensional image of the oral structure S acquired by the shape measurement camera 14 can be converted into a three-dimensional image using methods such as triangulation.

[0036] The OCT body 22 transmits tomographic light (e.g., near-infrared light) to the oral cavity structure S and detects reflected light (scattered light) within the oral cavity structure S, specifically at each cross-section, to obtain an internal cross-sectional image of the oral cavity structure S. The OCT body 22 is a typical device that utilizes the coherence property of tomographic light to obtain tomographic information about the interior of an object. For example, the tomographic light is broadband low-coherence light with a short coherence distance, preferably near-infrared light, specifically near-infrared light with a wavelength of 750 to 1500 nm. The OCT scan probe 24 is a device that illuminates the desired location of the oral cavity structure S with the tomographic light emitted by the OCT body 22 and transmits the reflected light from the oral cavity structure S back to the OCT body 22. The OCT scanning probe 24 may include: a collimator 24a, which focuses the tomographic measurement light and its reflected light; a mirror 24b, which reflects the focused tomographic measurement light to the desired imaging position of the oral structure S and transmits the reflected light reflected from the oral structure S to the collimator 24a; and an objective lens 24c, which focuses the measurement light reflected from the mirror 24b to the desired imaging position of the oral structure S. The mirror 24b can be a MEMS mirror (micro electromechanical system mirror) capable of sequentially scanning the imaging position of the oral structure S by adjusting the reflection angle of the tomographic measurement light. For example, the mirror 24b can rotate about two axes (e.g., the x-axis and y-axis, which are orthogonal) to sequentially scan the plane where the oral structure S is located, illuminating the interior of the oral structure S with the tomographic measurement light in a direction perpendicular to the plane (orthogonal to the z-axis, x-axis, and y-axis) to obtain a three-dimensional tomographic image of the oral structure S.

[0037] The beam splitter 30 is a device that overlaps the optical paths of the shape measurement light irradiated by the shape measurement light projector 12 and the tomographic light irradiated by the OCT scanning probe 24, thereby overlapping the shape acquisition optical system formed by the shape measurement light projector 12 and the shape measurement camera 14 with the tomographic acquisition optical system formed by the OCT body 22 and the OCT scanning probe 24. For example, as Figure 3As shown, the beam splitter 30 can be a dichroic mirror 30 that transmits shape measurement light irradiated by the shape measurement light projector 12 and reflects tomographic light irradiated by the OCT scanning probe 24 to illuminate the oral structure S with both shape measurement light and tomographic light, and separates the reflected light for transmission to the shape acquisition optical system (specifically, the shape measurement camera 14) and the tomographic acquisition optical system (specifically, the OCT body 22). Since the shape acquisition optical system formed by the conventional shape measurement light projector 12 and shape measurement camera 14 and the tomographic acquisition optical system formed by the conventional OCT body 22 and OCT scanning probe 24 use measurement light from different regions, they cannot use the same optical path. However, as... Figure 3 As shown, when the dichroic mirror 30, which reflects the tomographic light and transmits the shape measurement light, is positioned where the shape measurement light of the shape measurement projector 12 passes through but is not included in the FOV (Field of View) region of the shape measurement camera 14, an integrated optical system can be formed where the respective measurement regions of the shape acquisition optical system and the tomographic acquisition optical system overlap, i.e., the ROI (Region of Interest) overlaps. Therefore, by overlapping the shape measurement light and the tomographic light and illuminating the oral cavity structure S, the dichroic mirror 30 can obtain an external surface shape image and an internal tomographic image of the oral cavity structure S.

[0038] In an embodiment of the present invention, an oral scanner with tomography function can set the position of a region of interest (ROI) for tomography of the overall image T of the oral structure obtained by the shape measurement camera 14, and can detect the position of a partial image p of the oral structure with the set ROI, transmit tomographic light to the position of the partial image p, and detect the reflected light reflected at the position of the partial image p to obtain an internal cross-sectional image of the ROI.

[0039] Figures 4 to 8 This diagram illustrates a method for tomographic imaging of the oral cavity using an oral scanner with tomographic imaging capabilities according to the present invention. To obtain a tomographic image of the oral cavity structure S according to the present invention, firstly, as... Figure 4 and Figure 8As shown, a shape measurement light projector 12 sequentially illuminates the oral cavity structure S, and a shape measurement camera 14 detects the reflected light formed by the reflection of the shape measurement light on the surface of the oral cavity structure S to obtain an overall image T of the oral cavity structure S (S10). The overall image T of the oral cavity structure S is an overall surface image T of the oral cavity structure S including the region of interest (ROI), such as the entire lower tooth, or the surface shape image T of a single tooth. Figure 5 This diagram illustrates an example of a 3D surface shape image T of an oral structure S obtained by performing surface scanning. For the overall surface shape image T of the oral structure S thus obtained, the location of the region of interest (ROI) for tomographic imaging is defined (S20, defining the ROI). For example, as... Figure 5 As shown, the position of the crown margin line 40 is displayed as the region of interest (ROI) in the three-dimensional surface shape image T of oral structures such as teeth.

[0040] Next, as Figure 6 As shown, the OCT body 22 and the OCT scanning probe 24 transmit tomographic measurement light along the set region of interest (ROI) and detect the reflected light reflected by each section inside the region of interest (ROI). That is, tomographic scanning is performed on the region of interest (ROI) to obtain an internal cross-sectional image of the region of interest (ROI) (S30). Figure 7 This is an example of performing a tomographic scan on a region of interest (ROI). For example... Figure 7 As shown in A, the tomographic scan is not performed on the entire oral structure S, but only on a portion of the oral structure S, namely the tomographic region 50 (indicated by the dashed line), based on the region of interest (ROI). Figure 7 Figure B is an example of a tomographic image of an oral structure S obtained at a location within a region of interest (ROI). Therefore, according to the present invention, the region of interest (ROI) defined in the overall surface shape image T of the oral structure S serves to guide the path or region for performing tomographic scanning. At this time, the position of a portion of the oral structure with the defined ROI can be detected, tomographic light can be transmitted to the position of the portion of the image p, and the reflected light reflected at the position of the portion of the image p can be detected to obtain an internal cross-sectional image of the ROI.

[0041] According to a more specific implementation of the present invention, the step (S30) of obtaining the internal cross-sectional image of the region of interest (ROI) includes the following steps. For example... Figures 6 to 8 As shown, according to the user's command or a pre-set program, the computed tomography (OCT) scan begins (S300, OCT mode). At this time, if the OCT body 22 is not powered or is in a state where the OCT body 22 is not ready for use, the OCT body 22 is activated to switch the OCT body 22 to a measurable state (S302).

[0042] When the OCT scan begins, firstly, shape measurement light is projected onto a predetermined location of the oral structure S, i.e., a portion of the oral structure S, using a shape measurement light projector 12. The reflected light formed by the shape measurement light reflecting off the surface of this portion of the oral structure S is then detected by a shape measurement camera 14 (S310). When the illumination of the portion of the oral structure S by the shape measurement light ends (S312), a partial image p of the oral structure S is obtained (referencing...). Figure 7 (S314). The obtained partial image p of the oral cavity structure S is a three-dimensional surface image of a portion of the oral cavity structure S, which is referred to as "patch data" as needed in this specification. Next, the partial image p of the oral cavity structure S obtained in step S314 is compared with the overall image T of the oral cavity structure S obtained in step S10 to detect the position of the partial image p in the overall image T of the oral cavity structure S, and to detect whether there is a region of interest (ROI) in the partial image p (S316). For convenience, the comparison of the partial image p of the oral cavity structure S with the overall image T of the oral cavity structure S to detect the position detection of the partial image p in the overall image T of the oral cavity structure S is called "Global Registration".

[0043] On the other hand, when the illumination of the shape measurement light ends (S312), the OCT body 22 transmits the tomographic measurement light to the portion of the oral structure S that was illuminated by the shape measurement light (S322), and detects the reflected light (scattered light) reflected inside the oral structure S to obtain an internal cross-sectional image of the portion of the oral structure S (S324). For example, while the shape measurement light is illuminating the portion of the oral structure S (S310), a measurement signal (trigger signal) is transmitted to the OCT body 22, and the OCT body 22 executes a standby mode (S320) without illuminating the tomographic measurement light until the illumination of the shape measurement light ends (S312). When the standby mode (S320) ends, the tomographic measurement light can be transmitted to the portion of the oral structure S that was illuminated by the shape measurement light (S322), and the reflected light (scattered light) reflected inside the oral structure S can be detected to obtain an internal cross-sectional image of the portion of the oral structure S (S324). The obtained two-dimensional tomography image (e.g., Figure 7 The image B is called an "OCTB-scanimage". After obtaining an internal cross-sectional image of a portion of the oral cavity structure S, the tomographic illumination ends (S326). Figure 7 As shown, for a partial image p of an oral structure S, it is preferable to obtain one internal cross-sectional image, but multiple images, such as two to five cross-sectional images, can be obtained at equal intervals as needed.

[0044] In this invention, shape measurement light and tomographic light are not irradiated simultaneously, but alternately. Preferably, the tomographic light is irradiated immediately after the shape measurement light irradiation ends. If a partial image p of the oral structure S is obtained by irradiating the shape measurement light (refer to...) Figure 7When the shape measurement light is simultaneously irradiated onto the OCT body 22, the reflected light from the shape measurement light cannot be correctly detected due to interference from the tomographic light, making it difficult to obtain a correct partial image p. In one embodiment of the present invention, after the shape measurement light is irradiated (S310), the irradiation of the shape measurement light ends (S312), and the shape measurement time required to obtain a partial image p varies depending on the performance of the shape measurement light projector 12 and the shape measurement camera 14, but is typically a specified short time of tens of milliseconds (ms). Therefore, after transmitting the measurement signal (trigger signal) to the OCT body 22, the waiting mode time of the OCT body 22 can be set to be the same as the "shape measurement time". If the irradiation period of the shape measurement light and the irradiation period of the tomographic light overlap, as described above, it is difficult to obtain a correct partial image p due to light interference. Conversely, if the time difference between the illumination of the shape measurement light and the illumination of the tomographic measurement light is large, the position of the device changes due to the characteristics of the hand-held device, resulting in the position of the obtained partial image p being different from the position of the obtained tomographic image, making it difficult to obtain a tomographic image of the correct position.

[0045] Next, in the partial image p position detection step (S316), when a region of interest (ROI) exists in the partial image p, the cross-sectional image of the portion of the oral structure S obtained in step S324 is used as the position of the partial image p. Specifically, the internal cross-sectional image of the ROI of the partial image p is used (S330, OCT image registration). That is, the internal cross-sectional image of the current position of the partial image p obtained in the overall image T is registered, i.e., stored in the memory (not shown) inside the scanner. Conversely, when there is no ROI in the partial image p, the cross-sectional image of the portion of the oral structure S obtained in step S324 is discarded. In this invention, since the partial image p of the oral structure S is a cross-sectional image used to confirm whether the cross-sectional image obtained at the corresponding partial position is a region of interest (ROI) and to confirm the position of the corresponding cross-sectional image, the partial image p of the oral structure S can be discarded without being stored separately after registering or discarding the cross-sectional image at the corresponding position (i.e., the position of the partial image p).

[0046] In this way, after obtaining a cross-sectional image of one part and registering or discarding it, the oral scanner can be moved to the next position, that is, another part of the oral structure S, and a start trigger signal is transmitted to the shape measurement light projector 12 to repeat the above process, detect the overall region of interest (ROI) set in the overall image T of the oral structure, and obtain the internal cross-sectional image of the region of interest (ROI).

[0047] According to this specific example, based on the information of the obtained surface shape image T of the oral cavity structure S, when a region of interest exists in a specific portion image p of the oral cavity structure S, a tomographic image obtained in the corresponding specific portion of the oral cavity structure S is used; when a region of interest does not exist in the specific portion image p of the oral cavity structure S, the tomographic image obtained in the corresponding specific portion of the oral cavity structure S is discarded, thereby quickly and effectively obtaining the tomographic image of the desired portion. According to an implementation example of the present invention, a surface shape image T of the oral cavity structure S is acquired using shape measurement light, and a region of interest is extracted or specified from the acquired surface shape image T. Next, the oral cavity structure S is partially scanned again using shape measurement light to obtain a partial image p. When the position of the obtained partial image p is a position that includes the region of interest, a tomographic image is acquired at the corresponding position; when the position of the obtained partial image p is a position that does not include the region of interest, the tomographic image obtained at the corresponding position is discarded.

[0048] Figure 9 This is a diagram illustrating an example of performing tomographic imaging on a specific region of interest in the oral cavity according to the present invention. Figure 9 In the example shown, the location of tooth wear is set as the region of interest (ROI) 40, and tomography is performed on the tomographic region 50 formed along the ROI 40. Figure 8 (A). Tomographic results obtained at a specific location in region of interest 40 are shown in... Figure 9 B and C. Figure 9 B shows the cross-sectional shape of tooth wear as a result of tomographic imaging before treatment. Figure 9 C shows the cross-sectional shape of the tooth wear portion filled with resin as a result of post-treatment tomographic imaging.

[0049] Although the invention has been described above with reference to the accompanying drawings and exemplary embodiments, the invention is not limited to the contents shown in the figures and the embodiments described above. While reference numerals are used in the following claims to aid understanding, the scope of the appended claims is not limited to the reference numerals and the contents shown in the figures, but should be interpreted as covering all variations, equivalent configurations, and functions of the exemplary embodiments.

Claims

1. A method of tomography of an oral cavity, characterized by, include: The steps are as follows: illuminating oral structures with shape measurement light in sequence and detecting the reflected light formed by the reflection of the shape measurement light on the surface of the oral structures to obtain an overall image (T) of the oral structures; The step of setting the location of the region of interest for tomographic imaging for the overall image (T) of the oral structure; as well as The step of transmitting tomographic light along the defined region of interest and detecting reflected light reflected inside the region of interest to obtain an internal cross-sectional image of the region of interest. The steps for obtaining the internal cross-sectional image of the region of interest include: The steps are as follows: illuminating a portion of an oral cavity structure (S) with shape measurement light and detecting the reflected light formed by the reflection of the shape measurement light on the surface of the portion of the oral cavity structure (S) to obtain a partial image (p) of the structure (S); The steps include comparing a partial image (p) of the oral structure (S) with a whole image (T) of the oral structure (S) to detect the position of the partial image (p) in the whole image (T) of the oral structure (S), and detecting whether there is a region of interest in the partial image (p); The steps of transmitting tomographic light onto a portion of an oral structure (S) irradiated with the shape measurement light, and detecting the reflected light reflected inside the oral structure (S) to obtain an internal cross-sectional image of the portion of the oral structure (S); and When a region of interest exists in the partial image (p), the step of registering a cross-sectional image obtained from a portion of the oral structure (S) illuminated by the shape measurement light as an internal cross-sectional image of the region of interest in the partial image (p) is performed.

2. The method for tomographic imaging of the oral cavity according to claim 1, characterized in that, The region of interest defined in the surface shape image of the oral cavity structure guides the path or region for performing tomography.

3. The method for tomographic imaging of the oral cavity according to claim 1, characterized in that, The shape measurement light and the tomographic measurement light are not irradiated at the same time, but the tomographic measurement light is irradiated immediately after the shape measurement light irradiation ends.

4. The method for tomographic imaging of the oral cavity according to claim 1, characterized in that, When no region of interest is found in the partial image (p), the cross-sectional image obtained from the portion of the oral structure (S) illuminated by the shape measurement light is discarded.

5. The method for tomographic imaging of the oral cavity according to claim 1, characterized in that, The partial image (p) of the oral structure (S) is discarded after the cross-sectional image of the location of the registered partial image (p) is taken, and is not stored separately.

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