Method and apparatus for restoring tooth edge portions altered by scanning

Abstract

To improve quality of scan data of a tooth.SOLUTION: A method according to the present invention comprises the steps of: acquiring scan data of a tooth; deleting the scan data of an edge portion of the tooth; arranging the first data in which a plurality of plates is radially arranged so as to be imposed on the scan data; creating a first cross section curve and a second cross section curve indicating an outer shape line of the scan data with the deleted portion held therebetween on each cross section of the scan data cut by the plurality of plates of the first data; extending the first cross section curve and the second cross section curve in a direction of compensating for the scan data of the deleted portion in each cross section of the scan data cut by the plurality of plates of the first data; and reconstructing the edge portion of the tooth on the basis of the extended first cross section curve and the extended second cross section curve in each cross section of the scan data cut by the plurality of plates of the first data.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for restoring an edge portion of a tooth that has changed by scanning.

Background Art

[0002] Patent Document 1 discloses a method for estimating and restoring the shape of an abutment tooth form that has changed by scanning. The method described in Patent Document 1 deletes a provisional finish line of an edge portion of an abutment tooth, and extends a crown-side provisional finish line and a root-side provisional finish line in the deleted portion. Further, the method described in Patent Document 1 estimates and restores a finish line of an edge portion formed outside the edge portion of the scanned data that has been deleted, based on the extended crown-side provisional finish line and the extended root-side provisional finish line.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method of Patent Document 1, there is still room for improvement in terms of improving the quality of tooth scan data.

[0005] An object of the present invention is to provide a method and an apparatus capable of improving the quality of tooth scan data.

Means for Solving the Problems

[0006] A method according to an aspect of the present invention is a method for a computer to restore the shape of an edge portion of a tooth that has changed by scanning, the step of acquiring scan data of a tooth, In the scan data, a step of deleting the scan data of the edge portion of the tooth; A step of arranging first data in which a plurality of plates are arranged radially on the scan data; In each cross-section of the scan data cut by the plurality of plates of the first data, a step of creating a first cross-sectional curve and a second cross-sectional curve showing the outer contour line of the scan data with the deleted portion sandwiched therebetween; In each cross-section of the scan data cut by the plurality of plates of the first data, a step of extending the first cross-sectional curve and the second cross-sectional curve in a direction to supplement the scan data of the deleted portion; A step of restoring the edge portion of the tooth based on the extended first cross-sectional curve and the extended second cross-sectional curve in each cross-section of the scan data cut by the plurality of plates of the first data; including.

[0007] An apparatus according to an aspect of the present invention is An apparatus for restoring the form of the edge portion of a tooth changed by scanning, one or more processors, a memory storing instructions executable by the one or more processors, having, the instructions are a step of acquiring scan data of a tooth, In the scan data, a step of deleting the scan data of the edge portion of the tooth; A step of arranging first data in which a plurality of plates are arranged radially on the scan data; In each cross-section of the scan data cut by the plurality of plates of the first data, a step of creating a first cross-sectional curve and a second cross-sectional curve showing the outer contour line of the scan data with the deleted portion sandwiched therebetween; In each cross-section of the scan data cut by the plurality of plates of the first data, extending the first cross-sectional curve and the second cross-sectional curve in a direction to supplement the scan data of the deleted portion; Restoring the edge portion of the tooth based on the extended first cross-sectional curve and the extended second cross-sectional curve in each cross-section of the scan data cut by the plurality of plates of the first data; including.

Advantages of the Invention

[0008] According to the method and apparatus of the present invention, the quality of the scan data of teeth can be improved.

Brief Description of the Drawings

[0009]

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Mode for Carrying Out the Invention

[0010] (Background of the Invention) In Patent Document 1, a method for estimating and restoring the shape near the finish line and the finish line that the abutment tooth or the abutment tooth model originally has from the scan data obtained by scanning the abutment tooth or the abutment tooth model is disclosed.

[0011] However, the method described in Patent Document 1 can be applied to the estimated restoration of the edge portion of the abutment tooth or the abutment tooth model, but it is not suitable for estimating and restoring the edge portion of a tooth having a complex shape. For example, even in a carious cavity-forming tooth or a tooth having a retention groove, the margin of the carious cavity or the margin of the retention groove is rounded more than the actual shape by scanning. In the method described in Patent Document 1, there is a problem that it is difficult to restore the scan data of the edge portion having a complex shape such as the margin of the carious cavity or the margin of the retention groove to a form closer to the actual object.

[0012] Also, in the method described in Patent Document 1, there is a problem that the processing time for performing the estimated restoration tends to be long, and the form of the edge portion of the tooth cannot be restored in a short time.

[0013] Therefore, the present inventors have arrived at the following invention in order to solve these problems.

[0014] The method according to the first aspect of the present invention is A method for a computer to restore the form of the edge portion of a tooth changed by scanning, The step of obtaining the scan data of the tooth, In the scan data, deleting the scan data of the edge portion of the tooth; placing the first data in which a plurality of plates are arranged radially, on top of the scan data; In each cross-section of the scan data cut by the plurality of plates of the first data, creating a first cross-sectional curve and a second cross-sectional curve that indicate the outer contour line of the scan data, with the deleted portion sandwiched therebetween; In each cross-section of the scan data cut by the plurality of plates of the first data, extending the first cross-sectional curve and the second cross-sectional curve in a direction to supplement the scan data of the deleted portion; Restoring the edge portion of the tooth based on the extended first cross-sectional curve and the extended second cross-sectional curve in each cross-section of the scan data cut by the plurality of plates of the first data; including.

[0015] In the method according to the second aspect of the present invention, the step of restoring the edge portion of the tooth includes: In each cross-section of the scan data cut by the plurality of plates of the first data, calculating an intersection point where the extended first cross-sectional curve and the extended second cross-sectional curve intersect; Connecting the calculated intersection points to create an intersection line; Restoring the edge portion of the tooth based on the intersection line; may have.

[0016] The method according to the third aspect of the present invention further includes: extracting a boundary line surrounding the deleted portion in the scan data; Restoring the edge portion of the tooth based on the intersection line may include creating shape data from the boundary line to the intersection line.

[0017] In the method according to the fourth aspect of the present invention, the step of extending the first cross-sectional curve and the second cross-sectional curve is: In each of the cross-sections of the scan data cut by the plurality of plates of the first data, extending the first cross-sectional curve while maintaining the curvature or the rate of change of curvature of the first cross-sectional curve at the end of the first cross-sectional curve; In each of the cross-sections of the scan data cut by the plurality of plates of the first data, extending the second cross-sectional curve while maintaining the curvature or the rate of change of curvature of the second cross-sectional curve at the end of the second cross-sectional curve; may have.

[0018] In the method according to the fifth aspect of the present invention, the first data has a central axis where the plurality of plates intersect, The step of arranging the first data overlaid on the scan data may include arranging the central axis of the first data along the tooth axis direction of the tooth.

[0019] In the method according to the sixth aspect of the present invention, arranging the central axis of the first data along the tooth axis direction of the tooth may include arranging the central axis of the first data at the center of the tooth when viewed from the direction from the crown to the root of the tooth.

[0020] The method according to the seventh aspect of the present invention further includes a step of arranging a second data in which a plurality of plates are arranged overlaid on the scan data, in each of the cross-sections of the scan data cut by the plurality of plates of the second data, creating a third cross-sectional curve and a fourth cross-sectional curve indicating the outer contour line of the scan data with the deleted portion sandwiched therebetween, in each of the cross-sections of the scan data cut by the plurality of plates of the second data, extending the third cross-sectional curve and the fourth cross-sectional curve in a direction to supplement the scan data of the deleted portion, including The step of restoring the edge portion of the tooth may restore the edge portion of the tooth based on the extended first cross-sectional curve, the extended second cross-sectional curve, the extended third cross-sectional curve, and the extended fourth cross-sectional curve.

[0021] In the method according to the eighth aspect of the present invention, the step of restoring the edge portion of the tooth is calculating a first intersection point where the extended first cross-sectional curve and the extended second cross-sectional curve intersect in each of the cross-sections of the scan data cut by the plurality of plates of the first data; calculating a second intersection point where the extended third cross-sectional curve and the extended fourth cross-sectional curve intersect in each of the cross-sections of the scan data cut by the plurality of plates of the second data; creating an intersection line based on the calculated first intersection point and second intersection point; restoring the edge portion of the tooth based on the intersection line; may have.

[0022] The method according to the ninth aspect of the present invention further includes extracting a boundary line surrounding the deleted portion in the scan data, Restoring the edge portion of the tooth based on the intersection line may include creating shape data from the boundary line to the intersection line.

[0023] In the method according to the tenth aspect of the present invention, the first data has a central axis where the plurality of plates intersect, The step of arranging the first data overlaid on the scan data includes arranging the first data such that the central axis is along the tooth axis direction of the tooth, The step of arranging the second data overlaid on the scan data may include arranging the second data such that the arrangement direction of the plurality of plates intersects the tooth axis direction of the tooth.

[0024] In the method according to the 11th aspect of the present invention, the plurality of plates in the second data may be arranged at equal intervals.

[0025] The method according to the 12th aspect of the present invention further includes a step of arranging third data in which a plurality of plates are arranged along a second direction different from the first direction in which the plurality of plates in the second data are arranged, on the scan data; a step of creating a fifth cross-sectional curve and a sixth cross-sectional curve indicating an outer shape line of the scan data, with the deleted portion sandwiched therebetween, in each cross-section of the scan data cut by the plurality of plates in the third data; a step of extending the fifth cross-sectional curve and the sixth cross-sectional curve in a direction to supplement the scan data of the deleted portion, in each cross-section of the scan data cut by the plurality of plates in the third data; including The step of restoring the edge portion of the tooth may include restoring the edge portion of the tooth based on the extended first cross-sectional curve, the extended second cross-sectional curve, the extended third cross-sectional curve, the extended fourth cross-sectional curve, the extended fifth cross-sectional curve, and the extended sixth cross-sectional curve.

[0026] In the method according to the 13th aspect of the present invention, the plurality of plates in the third data may be arranged at equal intervals.

[0027] In the method according to the 14th aspect of the present invention, the number of the plurality of plates in the first data may be 60 or more and 3500 or less.

[0028] In the method according to the 15th aspect of the present invention, the plurality of plates in the first data may be arranged at equal intervals.

[0029] In the method according to the 16th aspect of the present invention, the edge portion of the tooth may include at least one of abutment teeth, cavities, retention grooves, or the edge portion of the dental arch.

[0030] The program according to the 17th aspect of the present invention causes a computer to execute the method of any one of the 1st to 16th aspects.

[0031] The computer-readable recording medium according to the 18th aspect of the present invention records a program for causing a computer to execute the method of any one of the 1st to 16th aspects.

[0032] The apparatus according to the 19th aspect of the present invention is an apparatus for restoring the shape of the edge portion of a tooth that has changed by scanning, one or more processors, a memory storing instructions executable by the one or more processors, and has the instructions being steps of acquiring scan data of a tooth, deleting the scan data of the edge portion of the tooth from the scan data, steps of arranging first data in which a plurality of plates are arranged radially on the scan data, in each of the cross-sections of the scan data cut by the plurality of plates of the first data, creating a first cross-sectional curve and a second cross-sectional curve indicating the outer contour line of the scan data with the deleted portion sandwiched therebetween, in each of the cross-sections of the scan data cut by the plurality of plates of the first data, extending the first cross-sectional curve and the second cross-sectional curve in a direction to supplement the scan data of the deleted portion, restoring the edge portion of the tooth based on the extended first cross-sectional curve and the extended second cross-sectional curve in each of the cross-sections of the scan data cut by the plurality of plates of the first data, and including.

[0033] Hereinafter, the present invention will be described with reference to the drawings. In all the following drawings, the same or corresponding parts are denoted by the same reference numerals, and duplicate explanations are omitted.

[0034] (Embodiment 1) [Method for Restoring the Edge Portion of Teeth Changed by Scanning] FIG. 1 is a flowchart of a method for restoring the edge portion of teeth changed by scanning according to Embodiment 1 of the present invention. FIG. 2 is a flowchart for explaining the process of restoring the edge portion of teeth based on the extended first cross-sectional curve and the extended second cross-sectional curve. The steps shown in FIGS. 1 and 2 are executed by a computer. FIGS. 3A-12 are schematic diagrams for explaining each step shown in FIGS. 1 and 2. In Embodiment 1, an example of restoring the edge portion of abutment teeth will be described.

[0035] As shown in FIG. 1, in step ST1, tooth scan data is acquired. For example, in step ST1, teeth are scanned by a scanning device to acquire tooth scan data. For example, as the scanning device, an intraoral scanner that scans the inside of a patient's oral cavity or a desktop scanner that scans a dental model can be used. Note that scanning teeth includes scanning actual teeth or scanning a dental model.

[0036] For example, the tooth scan data may be acquired by directly scanning the inside of a patient's oral cavity with an intraoral scanner. Also, in the case of an abutment tooth model, the tooth scan data may be acquired by placing the abutment tooth model on a stage and using a desktop scanner. Alternatively, the tooth scan data may be acquired by scanning the inside of the oral cavity from outside the patient's oral cavity using an intraoral scanner.

[0037] Also, the tooth scan data may be acquired by receiving it from an external device using a communication device.

[0038] The scan data obtained in step ST1 is a collection of points and represents the position information of each point. The scan data is often output in the form of point cloud data, or STL data with the front and back of the surface and the surface normal vector information when the triangles composed of three adjacent points are regarded as surfaces, or wireframe data composed of triangles connecting adjacent points, or polygon data with surfaces stretched over each triangle of the wireframe, etc. In dentistry, STL data is most commonly used and is spreading as a common format data with high compatibility among different manufacturers.

[0039] FIG. 3A is a schematic diagram showing an example of an actual tooth. FIG. 3B is a schematic diagram showing an example of the scan data of the abutment tooth before restoration. FIG. 3B is the scan data 10 obtained by scanning the actual tooth 100 shown in FIG. 3A with a scanning device. As shown in FIGS. 3A and 3B, in the scan data 10, the edge portion 11 is rounder than the edge portion 101 of the actual tooth 100.

[0040] Returning to FIG. 1, in step ST2, the edge portion 11 of the tooth in the scan data 10 is deleted. For example, in step ST2, the edge portion 11 of the tooth is deleted based on the information input by the user. Specifically, the user inputs the area of the edge portion 11 through an input interface. Based on the information input by the user, the edge portion 11 is identified and deleted from the scan data 10.

[0041] Alternatively, in step ST2, the edge portion 11 in the scan data 10 may be automatically detected and the detected edge portion 11 may be deleted. For example, the edge portion 11 may be detected based on the curvature or the change in curvature of the scan data 10.

[0042] FIG. 4 is a schematic diagram showing a process of deleting the edge portion of the tooth in the scan data. As shown in FIG. 4, in step ST2, the edge portion 11 of the scan data 10 is deleted. Specifically, in the scan data 10, the edge portion 11 is deleted, and the deleted portion 12 and the remaining portion 13 are formed. In the example shown in FIG. 4, since the edge portion 11 is formed in an annular shape, the deleted portion 12 has an annular shape.

[0043] Returning to FIG. 1, in step ST3, in the scan data 10, a boundary line surrounding the deleted portion 12 is extracted. For example, in step ST3, in the scan data 10, the boundary line is extracted by detecting the boundary between the deleted portion 12 and the remaining portion 13.

[0044] FIG. 5 is a schematic diagram showing a process of extracting the boundary line. As shown in FIG. 5, in step ST3, in the scan data 10, a boundary line BL1 surrounding the deleted portion 12 is extracted. The boundary line BL1 is a line defining the deleted portion 12. The boundary line BL1 indicates the boundary between the deleted portion 12 and the remaining portion 13 in the portion representing the outer shape, i.e., the contour, of the tooth.

[0045] In the scan data 10 of the abutment tooth, since the deleted portion 12 has an annular shape, the boundary line BL1 includes a first boundary line BL11 and a second boundary line BL12. The first boundary line BL11 and the second boundary line BL12 are formed with the deleted portion 12 sandwiched therebetween.

[0046] The first boundary line BL11 is a line defining the inner boundary of the deleted portion 12, and the second boundary line BL12 is a line defining the outer boundary of the deleted portion 12. In other words, the first boundary line BL11 is a line formed on the crown side with respect to the deleted portion 12, and the second boundary line BL12 is a line formed on the root side with respect to the first boundary line BL11 with respect to the deleted portion 12.

[0047] Note that when the scan data 10 is STL data, the extraction of the boundary line BL may be performed after converting it into polysurface data. By converting it into polysurface data, it becomes easier to extract the boundary line BL1.

[0048] Returning to FIG. 1, in step ST4, the first data in which a plurality of plates are arranged radially is superimposed on the scan data 10.

[0049] FIGS. 6A and 6B show an example of the first data in which a plurality of plates are arranged radially. FIG. 6A shows a plan view of the first data, and FIG. 6B shows a side view of the first data. As shown in FIGS. 6A and 6B, the first data 20 includes a plurality of plates 21. The plurality of plates 21 are arranged radially. The plurality of plates 21 intersect at the central axis CX1 of the first data 20 and are arranged at equal intervals. The plurality of plates 21 have the same shape and the same size. Each of the plurality of plates 21 has a rectangular shape.

[0050] The first data 20 is used to cut the scan data 10 with each of the plurality of plates 21 and obtain the cross-sectional data of the scan data 10. Based on the cross-sectional data of the scan data 10 obtained using the first data 20, a first cross-sectional curve and a second cross-sectional curve, which will be described later, are created.

[0051] For example, the number of the plurality of plates 21 is 60 or more and 3500 or less. Preferably, the number of the plurality of plates 21 is 90 or more and 600 or less. Thereby, the edge portion 11 of the tooth can be restored closer to the actual object. Also, the interval between the plurality of plates 21 is 1 μm or more and 400 μm or less.

[0052] As shown in FIG. 6A, the first data 20 has a circular shape in plan view. As shown in FIG. 6B, the first data 20 has a rectangular shape in side view. Note that the shape and dimensions of the first data 20 are designed so that it can be superimposed on the entire scan data 10.

[0053] Figures 7A and 7B are schematic diagrams showing the step of arranging the first data overlaid on the scan data. Figure 7A shows a view of the step of arranging the first data overlaid on the scan data as seen from a plane, and Figure 7B shows a view of the step of arranging the first data overlaid on the scan data as seen from a side. As shown in Figures 7A and 7B, in step ST4, the first data 20 is arranged overlaid on the scan data 10 so as to encompass the entire scan data 10. For example, in step ST4, the central axis CX1 of the first data 20 is arranged along the tooth axis direction of the teeth of the scan data 10. Also, when viewing the scan data 10 in a plan view, that is, from the direction from the tooth crown to the tooth root of the tooth, the central axis CX1 of the first data 20 is arranged at the center of the tooth of the scan data 10.

[0054] Returning to Figure 1, in step ST5, in each of the cross-sections of the scan data 10 cut by the plurality of plates 21 of the first data 20, with the deleted portion 12 sandwiched therebetween, a first cross-sectional curve and a second cross-sectional curve indicating the outer contour line of the scan data 10 are created.

[0055] The first data 20 is arranged so as to penetrate the scan data 10. For this reason, the scan data 10 can be cut by the plurality of plates 21 of the first data 20 to obtain cross-sectional data of the scan data 10.

[0056] Figure 8 is a schematic diagram showing the step of creating the first cross-sectional curve and the second cross-sectional curve. As shown in Figure 8, in step ST5, the outer contour lines of the teeth in each cross-section of the scan data 10 cut by the plurality of plates 21 are extracted, and based on the outer contour lines, a first cross-sectional curve DL1 and a second cross-sectional curve DL2 are created. Thereby, cross-sectional curve data 30 of the scan data 10 is obtained. The cross-sectional curve data 30 is formed by the first cross-sectional curve DL1 and the second cross-sectional curve DL2 created in each cross-section.

[0057] The tooth outer contour line is a line indicating the contour of the tooth in the scan data 10. In the scan data 10, there is no outer contour line in the deleted portion 12. Therefore, no cross-sectional curve is created for the deleted portion 12. Thus, in the cross-section of the scan data 10, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 are created with the deleted portion 12 in between.

[0058] In the example shown in FIG. 8, the first cross-sectional curve DL1 is a line created on the crown side with respect to the deleted portion 12, and the second cross-sectional curve DL2 is a line created on the root side with respect to the deleted portion 12.

[0059] Returning to FIG. 1, in step ST6, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 are extended in a direction to supplement the scan data 10 of the deleted portion 12.

[0060] FIG. 9 is a schematic diagram showing the process of extending the first cross-sectional curve and the second cross-sectional curve. As shown in FIG. 9, in step ST6, in the cross-sectional curve data 30 of the scan data 10, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 are extended in a direction to supplement the scan data 10 of the deleted portion 12.

[0061] For example, the first cross-sectional curve DL1 is extended while maintaining the curvature or the change in curvature at the end of the first cross-sectional curve DL1 connected to the deleted portion 12. The second cross-sectional curve DL2 is extended while maintaining the curvature or the change in curvature at the end of the second cross-sectional curve DL2 connected to the deleted portion 12. For example, the end of the first cross-sectional curve DL1 is an end located on the side of the deleted portion 12 and is the point where the first cross-sectional curve DL1 intersects the first boundary line BL11. The end of the second cross-sectional curve DL2 is an end located on the side of the deleted portion 12 and is the point where the second cross-sectional curve DL2 intersects the second boundary line BL12.

[0062] For example, the first cross-sectional curve DL1 extends from the end of the first cross-sectional curve DL1 by 0.5 mm or more and 1.0 mm or less. Preferably, the first cross-sectional curve DL1 extends by 0.64 mm from the end of the first cross-sectional curve DL1. The second cross-sectional curve DL2 extends from the end of the second cross-sectional curve DL2 by 0.5 mm or more and 1.0 mm or less. Preferably, the second cross-sectional curve DL2 extends by 0.64 mm from the end of the second cross-sectional curve DL2.

[0063] Returning to FIG. 1, in step ST7, based on the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2, the edge portion 11 of the tooth is restored. Step ST7 will be described with reference to FIG. 2.

[0064] As shown in FIG. 2, in step ST11, at each cross-section of the scan data 10 cut by the plurality of plates 21 of the first data 20, an intersection point where the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2 intersect is calculated.

[0065] The extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2 that are extended in step ST6 intersect with each other in the deleted portion 12. In step ST11, at each cross-section, an intersection point between the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2 is calculated.

[0066] In step ST12, the calculated intersection points are connected to create an intersection line. In step ST12, the intersection points calculated at each cross-section are three-dimensionally connected to create an intersection line.

[0067] FIG. 10 is a schematic diagram showing the intersection line. As shown in FIG. 10, a closed intersection line CL1 is created by three-dimensionally connecting the intersection points calculated at each cross-section.

[0068] Returning to FIG. 2, in step ST13, based on the intersection line CL1, the edge portion 11 of the tooth is restored. Specifically, step ST13 includes step ST14 of creating shape data from the boundary line BL1 to the intersection line CL1.

[0069] Step ST14 will be described with reference to FIG. 11. FIG. 11 is a schematic diagram showing an edge portion restored based on a boundary line and an intersection line. As shown in FIG. 11, in step ST14, shape data from the boundary line BL1 to the intersection line CL1 is created. Specifically, shape data from the first boundary line BL11 to the intersection line CL1 and shape data from the second boundary line BL12 to the intersection line CL1 are created. Thereby, the edge portion 14 can be restored to the deleted portion 12.

[0070] For example, in creating the shape data from the boundary line BL1 to the intersection line CL1, shape data that fits through a contour curve defining the shape from the boundary line BL1 to the intersection line CL1 may be created. Alternatively, in creating the shape data from the boundary line BL1 to the intersection line CL1, in each cross-section, shape data from the boundary line BL1 to the intersection line CL1 may be created along the extended first cross-section curve DL1 and the extended second cross-section curve DL2. Or, shape data may be created such that the distance between the boundary line BL1 and the intersection line CL1 is the shortest in each cross-section. Note that the creation of the shape data is not limited to these, and may be performed by any method capable of creating shape data closer to the actual edge portion 101.

[0071] FIG. 12 is a schematic diagram showing an example of the scan data of the restored abutment tooth. As shown in FIG. 12, the edge portion 14 of the restored scan data 10 has a sharper shape compared to the edge portion 11 before repair and is in a form closer to the actual object.

[0072] The restored edge portion 14 can be combined with the deleted portion 12 of the scan data 10 to obtain the scan data 10 having the repaired edge portion 14.

[0073] In addition, when the restored edge portion 14 is polysurface data, after converting the restored edge portion 14 into mesh data, it may be matched and combined with the deleted portion 12 of the scan data 10.

[0074] Furthermore, with reference to FIGS. 13A to 13I, the restoration state of the edge portion of the tooth will be described. FIGS. 13A to 13I are schematic diagrams showing a series of steps for restoring the edge portion of the tooth. FIGS. 13A to 13I are two-dimensional image diagrams of a series of steps in which the edge portion is restored by the method of restoring the edge portion of the tooth changed by the above-described scan.

[0075] FIG. 13A is a schematic diagram showing an example of the edge portion of an actual tooth. By scanning the edge portion 101 of the actual tooth 100 shown in FIG. 13A with a scanning device, scan data is acquired.

[0076] FIG. 13B is a schematic diagram showing scan data obtained by scanning the edge portion of the actual tooth shown in FIG. 13A, and shows the scan data of the tooth before restoration. As shown in FIG. 13B, in the scan data 10 of the tooth before restoration, the edge portion 11 is rounder than the edge portion 101 of the actual tooth 100 shown in FIG. 13A.

[0077] FIG. 13C is a schematic diagram for explaining the step of deleting the edge portion from the scan data. As shown in FIG. 13C, the edge portion 11 of the scan data 10 is deleted. In the scan data 10, a deleted portion 12 of the scan data of the edge portion 11 is provided.

[0078] FIG. 13D is a schematic diagram for explaining the step of extracting a boundary line. As shown in FIG. 13D, in the scan data 10, by detecting the boundary between the deleted portion 12 and the remaining portion 13, a boundary line BL1 is extracted. Specifically, a first boundary line BL11 and a second boundary line BL12 are extracted with the deleted portion 12 sandwiched therebetween. Note that the boundary line BL1 extends in the paper surface direction.

[0079] FIG. 13E is a schematic diagram for explaining the step of creating a first cross-sectional curve and a second cross-sectional curve. In FIG. 13E, by arranging the first data 20 on the scan data 10, in each cross-section of the scan data 10 cut by a plurality of plates 21 of the first data 20, a first cross-sectional curve DL1 and a second cross-sectional curve DL2 are created. Specifically, in each cross-section of the scan data 10 cut by a plurality of plates 21 of the first data 20, with the deleted portion 12 in between, a first cross-sectional curve DL1 and a second cross-sectional curve DL2 indicating the outer contour line of the scan data 10 are created. The outer contour line of the scan data 10 is the contour line of the remaining portion 13 in each cross-section.

[0080] FIG. 13F is a schematic diagram for explaining the step of extending the first cross-sectional curve and the second cross-sectional curve. As shown in FIG. 13F, in the deleted portion 12, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 are extended in the direction of supplementing the scan data 10 of the deleted portion 12.

[0081] For example, in each cross-section of the scan data 10 cut by a plurality of plates 21 of the first data 20, while maintaining the curvature or the rate of change of curvature of the first cross-sectional curve DL1 at the point where the first cross-sectional curve DL1 intersects the first boundary line BL11, the first cross-sectional curve DL1 is extended. Also, in each cross-section of the scan data 10 cut by a plurality of plates 21 of the first data 20, while maintaining the curvature or the rate of change of curvature of the second cross-sectional curve DL2 at the point where the second cross-sectional curve DL2 intersects the second boundary line BL12, the second cross-sectional curve DL2 is extended.

[0082] FIG. 13G is a schematic diagram for explaining the step of calculating the intersection point of the first cross-sectional curve and the second cross-sectional curve. As shown in FIG. 13G, in each cross-section, an intersection point P1 where the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2 intersect is calculated.

[0083] By three-dimensionally connecting the intersection points P1 calculated in each cross-section, an intersection line CL1 is created. The intersection line CL1 corresponds to the restored edge.

[0084] FIG. 13H is a schematic diagram for explaining the process of restoring the edge portion of a tooth. As shown in FIG. 13H, the edge portion 11 is restored based on the intersection line CL1. Specifically, an edge portion 14 restored based on the boundary line BL1 and the intersection line CL1 is formed in the deleted portion 12. The restored edge portion 14 is obtained by creating shape data from the boundary line BL1 to the intersection line CL1. For example, in each cross-section, by creating shape data from the boundary line BL1 to the intersection line CL1 along the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2, the edge portion 14 restored in the deleted portion 12 is created.

[0085] FIG. 13I is a schematic diagram showing an example of the edge portion of a tooth after restoration. As shown in FIG. 13I, the repaired edge portion 14 is arranged in the portion 12 deleted from the scan data 10 and combined with the scan data 10.

[0086] FIG. 14 is a schematic diagram for explaining the edge portion of a tooth before and after restoration. In FIG. 14, the dashed line indicated by reference numeral 11 indicates the scanned edge portion before repair, and the solid line indicated by reference numeral 14 indicates the edge portion 14 after restoration. As shown in FIG. 14, the scan data 10 having a sharp edge portion 14 closer to the actual form than the edge portion 11 before repair is restored.

[0087] [Restoring device] FIG. 15 is a schematic block diagram showing the configuration of a device for restoring the edge portion of a tooth changed by scanning according to Embodiment 1 of the present invention.

[0088] As shown in FIG. 15, the restoring device 50 is a device that implements the above-described method, acquires the scan data 10 before repair, and outputs the scan data 10 after repair in which the edge portion 11 is restored. The restoring device 50 is, for example, a computer.

[0089] For example, the scan data 10 before repair is acquired by a scanning device and transmitted to a restoration device 50. The scan data 10 after repair is transmitted to a manufacturing device or the like that manufactures a prosthesis. Note that the restoration device 50 may create design data for manufacturing a prosthesis based on the scan data 10 after repair. In this case, the restoration device outputs the design data of the prosthesis.

[0090] The restoration device 50 includes one or more processors 51, a memory 52, and a communication unit 53.

[0091] The processor 51 is, for example, a central processing unit (CPU), a microprocessor, or other processing unit capable of executing computer-executable instructions. The processor 51 is capable of executing instructions stored in the memory 52.

[0092] The memory 52 stores data of the restoration device 50. The memory 52 includes, for example, a computer recording medium, and includes RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, DVD or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any medium that can be used to store desired information and can be accessed by the restoration device 50.

[0093] The memory 52 stores a program for executing the above-described method. Further, the memory 52 may store a program for creating design data of a prosthesis device.

[0094] The communication unit 53 communicates with an external device. The communication unit 53 includes a circuit that communicates with an external device in accordance with a predetermined communication standard. The predetermined communication standard includes, for example, LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), USB, HDMI (registered trademark), CAN (controller area network), SPI (Serial Peripheral Interface).

[0095] The communication unit 53 receives scan data from the scanning device via a network, for example. Also, the communication unit 53 transmits the scan data 10 after the repair of the mending device to the manufacturing device or the like via a network, for example.

[0096] [Effect] According to the method for restoring the edge portion of a tooth changed by scanning in Embodiment 1 of the present invention, the following effects can be achieved.

[0097] The method of Embodiment 1 according to the present invention is a method for a computer to restore the shape of the edge portion of a tooth changed by scanning, and includes steps ST1 to ST7 executed by a computer. Step ST1 acquires the scan data 10 of the tooth. Step ST2 deletes the scan data of the edge portion 11 of the tooth from the scan data 10. Step ST3 extracts a boundary line BL1 surrounding the deleted portion 12 from the scan data 10. Step ST4 arranges the first data 20 in which a plurality of plates 21 are arranged radially on top of the scan data 10. Step ST5 creates a first cross-sectional curve DL1 and a second cross-sectional curve DL2 indicating the outer contour line of the scan data 10 with the deleted portion 12 sandwiched therebetween in each cross-section of the scan data 10 cut by the plurality of plates 21 of the first data 20. Step ST6 extends the first cross-sectional curve DL1 and the second cross-sectional curve DL2 in a direction to supplement the scan data of the deleted portion 12 in each cross-section of the scan data 10 cut by the plurality of plates 21 of the first data 20. Step ST7 restores the edge portion 11 of the tooth based on the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2 in each cross-section of the scan data 10 cut by the plurality of plates 21 of the first data 20.

[0098] With such a configuration, the quality of the tooth scan data 10 can be improved. Specifically, the edge portion that has changed into a round shape by scanning can be restored to a form closer to the actual object. Also, according to the method of Embodiment 1, it can be applied to various tooth edge portions. For example, even for edge portions having complex shapes such as the margin shape of a cavity or a retention groove, and tooth alignment data, they can be restored to a form closer to the actual object.

[0099] Also, according to the method of Embodiment 1, the edge portion can be restored in a short time. For example, in the case of restoring the edge portion of a abutment tooth, the edge portion can be restored within 10 minutes.

[0100] The step ST7 of restoring the tooth edge portion 11 includes a step ST11 of calculating an intersection point, a step ST12 of creating an intersection line, and a step ST13 of restoring the edge portion 11. In step ST11, at each cross-section of the scan data 10 cut by a plurality of plates 21 of the first data 20, an intersection point P1 where the extended first cross-section curve DL1 and the extended second cross-section curve DL2 intersect is calculated. Step ST12 is to connect the calculated intersection points P1 to create an intersection line CL1. Step ST13 is to restore the tooth edge portion 11 based on the intersection line. With such a configuration, the edge portion 11 can be restored to a form closer to the actual object, and the quality of the scan data 10 can be further improved.

[0101] The step ST13 of restoring the edge portion 11 has a step ST14 of creating shape data from the boundary line BL1 to the intersection line CL1. With such a configuration, the edge portion 11 can be restored to a form closer to the actual object, and the quality of the scan data 10 can be further improved. Also, the edge portion 11 can be restored in a shorter time.

[0102] The step ST6 of extending the first cross-sectional curve DL1 and the second cross-sectional curve DL2 includes the step of extending the first cross-sectional curve and the step of extending the second cross-sectional curve DL2. The step of extending the first cross-sectional curve maintains the curvature or the rate of change of curvature of the first cross-sectional curve DL1 at the end of the first cross-sectional curve DL1 and extends the first cross-sectional curve DL1 in each cross-section of the scan data 10 cut by the plurality of plates 21 of the first data 20. The step of extending the second cross-sectional curve DL2 maintains the curvature or the rate of change of curvature of the second cross-sectional curve DL2 at the end of the second cross-sectional curve DL2 and extends the second cross-sectional curve DL2 in each cross-section of the scan data 10 cut by the plurality of plates 21 of the first data 20. With such a configuration, the edge portion 11 can be restored to a form closer to the actual object, and the quality of the scan data 10 can be further improved.

[0103] The first data 20 has a central axis CX1 where the plurality of plates 21 intersect. The step ST4 of arranging the first data 20 overlaid on the scan data 10 includes the step of arranging the central axis CX1 of the first data 20 along the tooth axis direction of the tooth. With such a configuration, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 indicating the outer contour line of the scan data 10 can be created with high accuracy. Thereby, the edge portion 11 can be restored to a form closer to the actual object, and the quality of the scan data 10 can be further improved.

[0104] The step of arranging the central axis CX1 of the first data 20 along the tooth axis direction of the tooth includes the step of arranging the central axis CX1 of the first data 20 at the center of the tooth when viewed from the direction from the tooth crown to the tooth root of the tooth. With such a configuration, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 can be created with higher accuracy. Thereby, the edge portion 11 can be restored to a form closer to the actual object, and the quality of the scan data 10 can be further improved.

[0105] The number of the plurality of plates 21 in the first data 20 is 60 or more and 3500 or less. Preferably, the number of the plurality of plates 21 is 90 or more and 600 or less. With such a configuration, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 can be created with higher accuracy. Thereby, the edge portion 11 of the tooth can be restored closer to the actual object, and the quality of the scan data 10 can be further improved.

[0106] The plurality of plates in the first data are arranged at equal intervals. With such a configuration, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 can be created with higher accuracy. Thereby, the edge portion 11 of the tooth can be restored closer to the actual object, and the quality of the scan data 10 can be further improved.

[0107] The restoration device 50 of the first embodiment includes one or more processors 51 and a memory 52 that stores instructions executable by the one or more processors 51. The instructions include the steps of the method described above. With such a configuration, the same effects as those of the method described above can be achieved.

[0108] In the first embodiment, an example in which the method includes the step ST3 of extracting the boundary line BL1 has been described, but the present invention is not limited thereto. For example, the method may not include the step ST3 of extracting the boundary line BL1. In this case, in step ST7, the shape data of the deleted portion may be created based on the extended first cross-sectional curve DL1, the extended second cross-sectional curve DL2, and the intersection line CL1.

[0109] In the first embodiment, an example in which the plurality of plates 21 in the first data 20 have a rectangular shape has been described, but the present invention is not limited thereto. The shape of the plurality of plates 21 is not limited to a rectangular shape. For example, the shape of the plurality of plates 21 may be an elliptical shape or a polygonal shape.

[0110] In Embodiment 1, an example in which a plurality of plates 21 in the first data 20 are arranged at equal intervals has been described, but the present invention is not limited to this. For example, the intervals between the plurality of plates 21 may be different.

[0111] In Embodiment 1, an example in which the edge portion 11 of a tooth is restored using the scan data of abutment teeth has been described, but the present invention is not limited to this. For example, the edge portion 11 of a tooth may be an abutment tooth cavity, a retention groove, or an edge portion (margin portion) of a dental arch. Further, the edge portion 11 of a tooth may be the edge portion 11 of a dental model.

[0112] FIG. 16A is a schematic diagram showing an example of scan data of a cavity-forming tooth before restoration. FIG. 16B is a schematic diagram showing an example of scan data of a cavity-forming tooth before restoration. In FIGS. 16A and 16B, the edge portion before restoration is denoted by reference numeral "11A", and the edge portion after restoration is denoted by reference numeral "14A". In the examples shown in FIGS. 16A and 16B, the edge portion 11A of the scan data 10A of the cavity-forming tooth, that is, the margin of the cavity 15, is restored by the method.

[0113] Comparing the edge portion 11A before restoration shown in FIG. 16A with the edge portion 14A after restoration shown in FIG. 16B, the edge portion 14A after restoration has a sharper shape than the edge portion 11A before restoration, and is restored to a form close to the margin of the actual cavity 15.

[0114] FIG. 17A is a schematic diagram showing an example of scan data of a tooth having a retention groove before restoration. FIG. 17B is a schematic diagram showing an example of scan data of a tooth having a retention groove after restoration. In FIGS. 17A and 17B, the edge portion before restoration is denoted by reference numeral "11B", and the edge portion after restoration is denoted by reference numeral "14B". In the examples shown in FIGS. 17A and 17B, the edge portion 11B of the scan data 10B of the tooth having a retention groove, that is, the margin of the retention groove 16, is restored by the method.

[0115] When comparing the edge portion 11B before restoration shown in Fig. 17A with the edge portion 14B after restoration shown in Fig. 17B, the edge portion 14B after repair has a sharper shape than the edge portion 11B before repair, and is restored to a form close to the margin of the maintenance groove 16 of the actual object.

[0116] Fig. 18A is a schematic diagram showing an example of scan data of a dental arch before restoration. Fig. 18B is an enlarged schematic diagram of the Z1 portion shown in Fig. 18. Fig. 18C is a schematic diagram showing an example of scan data of a dental arch after restoration. Fig. 18D is an enlarged schematic diagram of the Z2 portion shown in Fig. 18C. In Figs. 18A - 18D, the edge portion before restoration is indicated by the symbol "11C", and the edge portion after restoration is indicated by the symbol "14C". In the examples shown in Figs. 18A - 18D, in the scan data 10C of the dental arch, the edge portion 11C of the abutment tooth of the canine tooth, that is, the margin in the abutment tooth of the canine tooth, is restored by the method. Further, when implementing the method, the abutment tooth of the canine tooth is separated from the dental arch. That is, the method is implemented on the portion of the scan data 10C of the dental arch where the abutment tooth of the canine tooth is arranged. Thereby, the arithmetic processing can be reduced, and the edge portion 11C can be restored in a short time. In the examples shown in Figs. 18A - 18D, an example of separating the abutment tooth of the canine tooth from the dental arch when implementing the method has been described, but it is not limited thereto. For example, the method may be implemented without separating the abutment tooth from the dental arch. Also, the abutment tooth of the canine tooth is an example, and the method may be implemented for other abutment teeth.

[0117] When comparing the edge portion 11C of the abutment tooth of the canine tooth before restoration shown in Figs. 18A and 18B with the edge portion 14C of the abutment tooth of the canine tooth after restoration shown in Figs. 18C and 18D, the edge portion 14C after restoration has a sharper shape than the edge portion 11C before restoration, and is restored to a form close to the edge portion of the actual abutment tooth of the canine tooth, that is, the margin.

[0118] FIG. 18E is a schematic cross-sectional view taken along line A-A shown in FIG. 18D. FIG. 18F is a schematic enlarged view of portion Z3 shown in FIG. 18E. FIGS. 18E and 18F show the edge portion 11C before restoration by a dotted line and the edge portion 14C after restoration by a solid line. As can be seen from FIGS. 18E and 18F, the edge portion 14C after restoration has a sharper shape than the edge portion 11C before restoration and is restored to the form of the edge portion of the abutment tooth of an actual canine tooth, i.e., a form close to the margin.

[0119] Thus, according to the method of Embodiment 1, even an edge portion having a complex shape can be restored with high accuracy.

[0120] In Embodiment 1, the components of the restoration device 50 may be changed, added, deleted, integrated, or divided. For example, the restoration device 50 may not include the communication unit 53. The restoration device 50 may include a scanning device. Alternatively, the restoration device 50 may store a program for designing a prosthetic device in the memory 52.

[0121] In Embodiment 1, examples of the method and device have been described, but the present invention is not limited thereto. It may also be realized by a program for executing the method of Embodiment 1 or a computer-readable recording medium recording the program for executing the method. For example, the computer-readable medium may include the method of Embodiment 1 as computer-readable instructions executable by a processor. The computer-readable medium may include various types of volatile and non-volatile recording media, and may include, for example, random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), electrically programmable read only memory (PROM), electrically erasable read only memory (EPROM), flash memory, some other tangible data storage devices, or some combinations thereof.

[0122] The method and apparatus according to Embodiment 1 may be included in a method, apparatus, or system for manufacturing a prosthetic device.

[0123] (Embodiment 2) The method according to Embodiment 2 of the present invention will be described.

[0124] In Embodiment 2, mainly the differences from Embodiment 1 will be described. In Embodiment 2, the same reference numerals will be used for the same or equivalent configurations as in Embodiment 1, and the description overlapping with Embodiment 1 will be omitted.

[0125] FIG. 19 is a flowchart of a method for restoring an edge portion of a tooth changed by scanning according to Embodiment 2 of the present invention. FIG. 20 is a flowchart for explaining a process of restoring an edge portion of a tooth based on an extended first cross-sectional curve, an extended second cross-sectional curve, an extended third cross-sectional curve, and an extended fourth cross-sectional curve.

[0126] In Embodiment 2, it is different from Embodiment 1 in that the edge portion 11A of the tooth is restored using the second data.

[0127] Note that in Embodiment 2, steps ST21 to ST26 shown in FIG. 19 are the same as steps ST1 to ST6 in Embodiment 1, and steps ST31, ST34, and ST35 shown in FIG. 20 are the same as steps ST11, ST13, and ST14 in Embodiment 1. Therefore, the detailed description of these steps will be omitted.

[0128] Also, in Embodiment 2, an example of restoring an edge portion of the scan data of a cavity-forming tooth, that is, a margin of the cavity, will be described.

[0129] As shown in FIG. 19, in step ST21, scan data of a cavity-forming tooth is acquired.

[0130] FIG. 21 is a schematic diagram showing an example of scan data of a cavity-formed tooth before restoration. FIG. 21 is a plan view of the cavity-formed tooth, that is, a view seen from the direction from the tooth crown toward the tooth root. As shown in FIG. 21, in the scan data 10A of the cavity-formed tooth before restoration, the margin of the cavity 15, which is the edge portion 11A, is rounded.

[0131] Returning to FIG. 19, in step ST22, the edge portion 11A of the cavity-formed tooth is deleted.

[0132] In step ST23, a boundary line BL1 surrounding the deleted portion in the scan data 10A of the cavity-formed tooth is extracted.

[0133] In step ST24, the first data 20 is arranged overlaid on the scan data 10A.

[0134] FIG. 22 is a schematic diagram showing the process of arranging the first data overlaid on the scan data. As shown in FIG. 22, the first data 20 is arranged overlaid on the scan data 10A such that the central axis CX1 of the first data 20 is along the tooth axis direction of the cavity-formed tooth.

[0135] Returning to FIG. 19, in step ST25, in each of the cross-sections of the scan data 10A cut by the plurality of plates 21 of the first data 20, with the deleted portion sandwiched therebetween, a first cross-sectional curve DL1 and a second cross-sectional curve DL2 indicating the outer shape line of the scan data 10A are created.

[0136] In step ST25, the first cross-sectional curve DL1 and the second cross-sectional curve DL2 are extended in the direction of supplementing the scan data of the deleted portion.

[0137] In step ST26, the second data 22 in which the plurality of plates 23 are arranged is arranged overlaid on the scan data 10A.

[0138] FIG. 23 is a perspective view showing an example of second data in which a plurality of plates are arranged. As shown in FIG. 23, the second data 22 includes a plurality of plates 23. The plurality of plates 23 are arranged in one direction. The plurality of plates 23 are arranged parallel to each other. The plurality of plates 23 are arranged at equal intervals in one direction. The one direction is the direction in which the central axis CX2 of the second data 22 extends.

[0139] The plurality of plates 23 have the same shape and the same size. Each of the plurality of plates 23 has a disc shape.

[0140] The second data 22 is used to cut the scan data 10A with each of the plurality of plates 23 and obtain cross-sectional data of the scan data 10A. Based on the cross-sectional data of the scan data 10A obtained using the second data 22, a third cross-sectional curve and a fourth cross-sectional curve described later are created.

[0141] The second data 22 is disposed so as to penetrate the scan data 10A. Therefore, the scan data 10A can be cut by the plurality of plates 23 of the second data 22 to obtain cross-sectional data of the scan data 10A.

[0142] FIG. 24 is a schematic view showing a step of arranging the second data on top of the scan data. As shown in FIG. 24, the second data 22 is arranged on top of the scan data 10A such that the arrangement direction of the plurality of plates 23 intersects the tooth axis direction of the cavity-forming tooth. In Embodiment 2, the second data 22 is arranged on top of the scan data 10A such that the arrangement direction of the plurality of plates 23 is orthogonal to the tooth axis direction of the cavity-forming tooth.

[0143] Returning to FIG. 19, in step ST27, in each of the cross-sections of the scan data 10A cut by the plurality of plates 23 of the second data 22, a third cross-sectional curve and a fourth cross-sectional curve indicating the outer contour line of the scan data 10A are created with the deleted portions sandwiched therebetween.

[0144] FIG. 25 is a schematic diagram showing the process of creating the third cross-sectional curve and the extended fourth cross-sectional curve. Note that in FIG. 25, one side of the cross-sectional curve data 31 of the scan data 10A is shown, and the illustration of the other side is omitted. As shown in FIG. 25, in each cross-section of the scan data 10A cut by the plurality of plates 23 of the second data 22, with the deleted portion 12 in between, a third cross-sectional curve DL3 and a fourth cross-sectional curve DL4 indicating the outer contour line of the scan data 10A are created. The outer contour line of the scan data 10A means the contour line of the cavity-forming tooth.

[0145] In the example shown in FIG. 25, the third cross-sectional curve DL3 is created on the crown side of the deleted portion 12A, and the fourth cross-sectional curve DL4 is created on the crown side of the deleted portion 12A.

[0146] Returning to FIG. 19, in step ST29, the third cross-sectional curve DL3 and the fourth cross-sectional curve DL4 are extended in the direction of supplementing the scan data 10A of the deleted portion 12A. The way of extending the third cross-sectional curve DL3 and the fourth cross-sectional curve DL4 is the same as the way of extending the first cross-sectional curve DL1 and the second cross-sectional curve DL2.

[0147] In step ST30, based on the extended first cross-sectional curve DL1, the extended second cross-sectional curve DL2, the extended third cross-sectional curve DL3, and the extended fourth cross-sectional curve DL4, the edge portion 11A of the cavity-forming tooth is restored. Step ST30 will be described with reference to FIG. 20.

[0148] As shown in FIG. 20, in step ST31, in each cross-section of the scan data 10A cut by the plurality of plates 21 of the first data 20, a first intersection point where the extended first cross-sectional curve DL1 and the extended second cross-sectional curve DL2 intersect is calculated.

[0149] In step ST32, in each cross-section of the scan data 10A cut by the plurality of plates 23 of the second data 22, a second intersection point where the extended third cross-sectional curve DL3 and the extended fourth cross-sectional curve DL4 intersect is calculated.

[0150] In step ST29, the extended third cross-sectional curve DL3 and the extended fourth cross-sectional curve DL4 intersect with each other at the deleted portion 12A. In step ST32, at each cross-section, the second intersection point between the extended third cross-sectional curve DL3 and the extended fourth cross-sectional curve DL4 is calculated.

[0151] In step ST33, an intersection line CL1 is created based on the calculated first intersection point and second intersection point. Specifically, in each cross-section, the first intersection point and the second intersection point calculated are three-dimensionally connected to create the intersection line CL1. For example, at the first intersection point and the second intersection point, the points closest to each other are connected to create the intersection line CL1.

[0152] In step ST34, the edge portion 11A of the cavity-forming tooth is restored based on the intersection line CL1. Specifically, step ST34 has a step ST35 of creating the edge portion 11A based on the boundary line BL1 and the intersection line CL1.

[0153] In step ST35, shape data from the boundary line BL1 to the intersection line CL1 is created. Thereby, the edge portion 14A can be restored to the deleted portion 12A.

[0154] [Effect] According to the method of Embodiment 2 of the present invention, the following effects can be achieved.

[0155] The method of Embodiment 2 according to the present invention restores the edge portion 11A of the scan data 10A of the cavity-forming tooth using the first data 20 and the second data 22. Specifically, the method of Embodiment 2 includes steps ST27 to ST29 in addition to Embodiment 1. Step ST27 arranges the second data 22 in which a plurality of plates 23 are arranged on top of the scan data 10A. Step ST28 creates a third cross-sectional curve DL3 and a fourth cross-sectional curve DL4 indicating the outer contour line of the scan data 10A with the deleted portion 12A sandwiched therebetween in each cross-section of the scan data 10A cut by the plurality of plates 23 of the second data 22. Step ST29 extends the third cross-sectional curve DL3 and the fourth cross-sectional curve DL4 in a direction to supplement the scan data of the deleted portion 12A in each cross-section of the scan data 10A cut by the plurality of plates 23 of the second data 22. Also, in the method of Embodiment 2, step ST30 of restoring the edge portion of the tooth restores the edge portion 11A of the cavity-forming tooth based on the extended first cross-sectional curve DL1, the extended second cross-sectional curve DL2, the extended third cross-sectional curve DL3, and the extended fourth cross-sectional curve DL4.

[0156] With such a configuration, the quality of the edge portion of the tooth in the scan data 10A can be further improved. For example, in the scan data 10A of the cavity-forming tooth, the edge portion 11A such as the margin of the cavity 15 can be restored closer to the actual object.

[0157] Thus, according to the method of Embodiment 2, using the first data 20 and the second data 22, the edge portion 11A of a tooth having a complex shape such as a cavity-forming tooth can be restored closer to the actual object. Thereby, higher-quality scan data 10A can be created.

[0158] Step ST30 includes a step ST31 of calculating a first intersection point, a step ST32 of calculating a second intersection point, a step ST33 of creating an intersection line, and a step ST34 of restoring an edge portion. Step ST31 calculates a first intersection point where an extended first cross-sectional curve DL1 and an extended second cross-sectional curve DL2 intersect in each cross-section of the scan data 10A cut by a plurality of plates 21 of the first data 20. Step ST32 calculates a second intersection point where an extended third cross-sectional curve DL3 and an extended fourth cross-sectional curve DL4 intersect in each cross-section of the scan data 10A cut by a plurality of plates 23 of the second data 22. Step ST33 creates an intersection line CL1 based on the calculated first intersection point and second intersection point. Step ST34 restores the edge portion 11A of the tooth based on the intersection line CL1. With such a configuration, the edge portion 11A of the tooth having a complex shape can be restored closer to the actual object.

[0159] The first data 20 has a central axis CX1 where a plurality of plates 21 intersect. The step ST24 of arranging the first data 20 overlaid on the scan data 10A includes arranging the first data 20 such that the central axis CX1 is along the tooth axis direction of the tooth. The step ST27 of arranging the second data 22 overlaid on the scan data 10A includes arranging the second data 22 such that the arrangement direction of the plurality of plates 23 intersects the tooth axis direction of the tooth. With such a configuration, the intersection line CL1 indicating the edge of the tooth can be created closer to the actual edge line. Thereby, the edge portion 11A of the tooth having a complex shape can be restored closer to the actual object.

[0160] In addition, in the second embodiment, an example of arranging the second data 22 overlaid on the scan data 10A such that the arrangement direction of the plurality of plates 23 intersects the tooth axis direction of the tooth has been described, but it is not limited thereto. For example, the second data 22 may be arranged overlaid on the scan data 10A such that the arrangement direction of the plurality of plates 23 is along the tooth axis direction of the tooth. Alternatively, the second data 22 may be arranged overlaid on the scan data 10A based on information input by the user.

[0161] In Embodiment 2, an example in which the second data 22 is arranged so as to overlap the entire scan data 10A has been described, but the present invention is not limited thereto. For example, the second data 22 may be arranged so as to partially overlap the scan data 10.

[0162] In Embodiment 2, an example in which each of the plurality of plates 23 of the second data 22 has a disk shape has been described, but the present invention is not limited thereto. For example, each of the plurality of plates 23 may have a plate shape, and may have a rectangular shape, a polygonal shape, or an elliptical shape when viewed in the thickness direction.

[0163] In Embodiment 2, an example in which the plurality of plates 23 of the second data 22 are arranged in parallel has been described, but the present invention is not limited thereto. For example, the plurality of plates 23 may be arranged in a curved line.

[0164] In Embodiment 2, an example in which the plurality of plates 23 of the second data 22 are arranged at equal intervals has been described, but the present invention is not limited thereto. For example, the plurality of plates 23 may be arranged at different intervals.

[0165] (Embodiment 3) A method according to Embodiment 3 of the present invention will be described.

[0166] In Embodiment 3, mainly the differences from Embodiment 2 will be described. In Embodiment 3, the same reference numerals will be given to the same or equivalent configurations as those in Embodiment 2 and will be described. Also, in Embodiment 3, the descriptions overlapping those in Embodiment 2 will be omitted.

[0167] FIG. 26A and FIG. 26B are flowcharts of a method for restoring an edge portion of a tooth changed by scanning according to Embodiment 3 of the present invention. FIG. 27 is a flowchart for explaining a step of restoring an edge portion of a tooth based on an extended first cross-sectional curve, an extended second cross-sectional curve, an extended third cross-sectional curve, an extended fourth cross-sectional curve, an extended fifth cross-sectional curve, and an extended sixth cross-sectional curve.

[0168] In Embodiment 3, it is different from Embodiment 2 in that the edge portion 11A of the tooth is restored using the third data.

[0169] Note that in Embodiment 3, steps ST41 to ST49 shown in FIG. 26A are the same as steps ST21 to ST29 in Embodiment 2, and steps ST61, ST62, ST65, and ST66 shown in FIG. 27 are the same as steps ST31, ST32, ST34, and ST35 in Embodiment 2. Therefore, detailed descriptions of these steps are omitted.

[0170] Also, in Embodiment 3, similar to Embodiment 2, an example of restoring the edge portion of the scanned data of the cavity-forming tooth, that is, the margin of the cavity, will be described.

[0171] As shown in FIG. 26A, steps ST41 to ST49 are performed. In Embodiment 3, in step ST47, the direction in which the plurality of plates 23 of the second data 22 are arranged is referred to as the "first direction".

[0172] As shown in FIG. 26B, in step ST50, third data in which a plurality of plates are arranged along a second direction is superimposed on the scanned data 10A and arranged. The second direction means a direction different from the first direction. For example, the second direction is a direction intersecting the first direction. In Embodiment 3, the second direction is orthogonal to the first direction. That is, the second direction is a direction along the tooth axis direction of the cavity-forming tooth.

[0173] FIG. 28 is a schematic diagram showing the step of superimposing and arranging the third data on the scanned data. As shown in FIG. 28, in step ST50, third data 24 in which a plurality of plates 25 are arranged along a second direction different from the first direction in which the plurality of plates 23 in the second data 22 are arranged is superimposed on the scanned data 10A and arranged.

[0174] Similar to the second data 22, the third data 24 includes a plurality of plates 25. The plurality of plates 25 are arranged in the second direction. The plurality of plates 23 are arranged at equal intervals in the second direction. The second direction is the direction in which the central axis CX3 of the third data extends.

[0175] The third data 24 is arranged such that the central axis CX3 of the third data 24 passes through the center of the cavity-forming tooth in a plan view.

[0176] The plurality of plates 25 have the same shape and the same size. Each of the plurality of plates 25 has a disc shape.

[0177] In Embodiment 3, the plurality of plates 25 of the third data 24 are the same as the plurality of plates 23 of the second data 22 except for the arrangement direction.

[0178] The third data 24 is used to cut the scan data 10A with each of the plurality of plates 25 and obtain the cross-sectional data of the scan data 10A. Based on the cross-sectional data of the scan data 10A obtained using the third data 24, a fifth cross-sectional curve and a sixth cross-sectional curve described later are created.

[0179] The third data 24 is arranged to penetrate the scan data 10A. Therefore, the scan data 10A can be cut by the plurality of plates 25 of the third data 24 to obtain the cross-sectional data of the scan data 10A.

[0180] Returning to FIG. 26B, in step ST51, in each of the cross-sections of the scan data 10A cut by the plurality of plates 25 of the third data 24, a fifth cross-sectional curve and a sixth cross-sectional curve indicating the outer contour line of the scan data 10A are created with the deleted portions sandwiched therebetween. Since step ST51 is the same as step ST48 for creating the third cross-sectional curve and the fourth cross-sectional curve, a detailed description thereof is omitted.

[0181] In step ST52, the fifth cross-sectional curve and the sixth cross-sectional curve are extended in the direction of supplementing the scan data of the deleted part. Since step ST52 is the same as step ST48 for extending the third cross-sectional curve and the fourth cross-sectional curve, detailed description thereof is omitted.

[0182] In step ST53, the edge portion of the tooth is restored based on the extended first cross-sectional curve, the extended second cross-sectional curve, the extended third cross-sectional curve, the extended fourth cross-sectional curve, the extended fifth cross-sectional curve, and the extended sixth cross-sectional curve. Step ST52 will be described with reference to FIG. 27.

[0183] As shown in FIG. 27, in step ST61, at each cross-section of the scan data 10A cut by the plurality of plates 21 of the first data 20, a first intersection point where the extended first cross-sectional curve and the extended second cross-sectional curve intersect is calculated.

[0184] In step ST62, at each cross-section of the scan data 10A cut by the plurality of plates 23 of the second data 22, a second intersection point where the extended third cross-sectional curve and the extended fourth cross-sectional curve intersect is calculated.

[0185] In step ST63, at each cross-section of the scan data 10A cut by the plurality of plates 25 of the third data 24, a third intersection point where the extended fifth cross-sectional curve and the extended sixth cross-sectional curve intersect is calculated. Step ST63 calculates the third intersection point in the same manner as step ST62.

[0186] In step ST64, an intersection line CL1 is created based on the calculated first intersection point, second intersection point, and third intersection point. Specifically, the first intersection point, second intersection point, and third intersection point calculated at each cross-section are three-dimensionally connected to create the intersection line CL1.

[0187] In step ST65, the edge portion 11A of the cavity-forming tooth is restored based on the intersection line CL1. Specifically, step ST65 has a step ST66 of creating the edge portion 11A based on the boundary line BL1 and the intersection line CL1.

[0188] In step ST66, shape data from the boundary line BL1 to the intersection line CL1 is created. Thereby, an edge portion can be restored to the portion 12A deleted in the scan data 10A.

[0189] [Effect] According to the method of Embodiment 3 according to the present invention, the following effects can be achieved.

[0190] The method of Embodiment 3 according to the present invention restores the edge portion 11A of the scan data 10A of the cavity-forming tooth using the first data 20, the second data 22, and the third data 24. Specifically, the method of Embodiment 3 includes steps ST50 to ST52 in addition to Embodiment 2. Step ST50 places the third data 24 in which a plurality of plates 25 are arranged along a second direction different from the first direction in which the plurality of plates 23 in the second data 22 are arranged, overlaid on the scan data 10A. Step ST51 creates a fifth cross-sectional curve and a sixth cross-sectional curve indicating the outer contour line of the scan data 10A, sandwiching the deleted portion 12A in each cross-section of the scan data 10A cut by the plurality of plates 25 of the third data 24. Step ST52 extends the fifth cross-sectional curve and the sixth cross-sectional curve in a direction to supplement the scan data of the deleted portion 12A in each cross-section of the scan data 10A cut by the plurality of plates 25 of the third data 24. Also, in the method of Embodiment 3, step ST53 for restoring the edge portion of the tooth restores the edge portion 11A of the cavity-forming tooth based on the extended first cross-sectional curve, the extended second cross-sectional curve, the extended third cross-sectional curve, the extended fourth cross-sectional curve, the extended fifth cross-sectional curve, and the extended sixth cross-sectional curve.

[0191] With such a configuration, the quality of the edge portion of the teeth in the scan data 10A can be further improved. For example, in the scan data 10A of the cavity-forming tooth, the edge portion 11A such as the margin of the cavity 15 can be restored closer to the actual object.

[0192] Thus, in the third embodiment, by restoring the edge portion 11A of the scan data 10A of the cavity-forming tooth using the first data 20, the second data 22, and the third data 24, the edge portion 11A can be restored with higher accuracy.

[0193] In the third embodiment, an example in which the plurality of plates 25 of the third data 24 are the same as the plurality of plates 23 of the second data 22 has been described, but the present invention is not limited to this. For example, the plurality of plates 25 of the third data 24 may be different from the plurality of plates 23 of the second data 22.

[0194] In the methods of the first to third embodiments described above, the steps may be changed, added, decreased, divided, and integrated according to the applied environment.

[0195] In the methods of the first to third embodiments described above, the order of the steps may be changed.

[0196] In this specification, terms such as "first" and "second" are used only for the purpose of explanation and should not be understood as indicating or implying relative importance or the order of technical features. The features limited to "first" and "second" explicitly or implicitly include one or more of the said features.

[0197] Although the present invention has been described in each embodiment with a certain degree of detail, the disclosed content of these embodiments should be changed in terms of the details of the configuration, and changes in the combination and order of elements in each embodiment can be realized without departing from the scope and spirit of the claimed invention.

Industrial Applicability

[0198] The method for restoring the edge portion of a tooth changed by scanning according to the present invention can restore the edge portion of the tooth damaged by scanning. Therefore, it is useful for an apparatus or method for manufacturing a prosthetic device, etc.

Explanation of Signs

[0199] 10, 10A, 10B, 10C Scan data 11, 11A, 11B, 11C Edge portion before restoration 12, 12A Deleted portion 13 Remaining portion 14, 14A, 14B, 14C Edge portion after restoration 20 First data 21 Plate 22 Second data 23 Plate 24 Third data 25 Plate 30, 31 Cross-sectional curve data 50 Restoration device 51 Processor 52 Memory 53 Communication unit 100 Actual tooth 101 Edge portion BL1 Boundary line BL11 First boundary line BL12 Second boundary line CL1 Intersection line CX1, CX2, CX3 Central axis DL1 First cross-sectional curve DL2 Second cross-sectional curve DL3 Third cross-sectional curve DL4 Fourth cross-sectional curve P1 Intersection point

Claims

1. A method in which a computer performs steps to restore the morphology of tooth edges that have been altered by scanning, comprising the steps of: Each of the steps is obtaining dental scan data; removing scan data of edge portions of the teeth from the scan data; A step of overlaying a first data set in which a plurality of plates are radially arranged on the scan data; creating a first cross-sectional curve and a second cross-sectional curve that indicate an outline line of the scan data, with the deleted portion sandwiched between the first cross-sectional curve and the second cross-sectional curve, in each cross-sectional surface of the scan data cut by the plurality of plates of the first data; Extending the first cross-section curve and the second cross-section curve in a direction to compensate for the deleted portion of the scan data in each cross-section of the scan data cut by the plurality of plates of the first data; restoring an edge portion of the tooth based on an extended first cross-section curve and an extended second cross-section curve in each cross-section of the scan data cut by the plurality of plates of the first data; A method comprising:

2. The step of restoring the tooth edge portion includes: Calculating an intersection point where the extended first cross-section curve and the extended second cross-section curve intersect in each cross-section of the scan data cut by the plurality of plates of the first data; connecting the calculated intersection points to generate an intersection line; Reconstructing the tooth edge portion based on the intersection line; having The method of claim 1.

3. Furthermore, extracting a boundary line surrounding the deleted portion from the scan data; Restoring the tooth edge portion based on the intersection line includes creating shape data from the boundary line to the intersection line. The method of claim 2.

4. The step of extending the first cross-sectional curve and the second cross-sectional curve includes: Extending the first cross-sectional curve while maintaining the curvature or the rate of change of the curvature of the first cross-sectional curve at an end of the first cross-sectional curve in each cross-section of the scan data cut by the plurality of plates of the first data; Extending the second cross-sectional curve while maintaining the curvature or the rate of change of the curvature of the second cross-sectional curve at an end of the second cross-sectional curve in each cross-section of the scan data cut by the plurality of plates of the first data; having The method according to claim 2 or 3.

5. The first data includes a central axis along which the plates intersect, The step of overlaying the first data on the scan data includes arranging the central axis of the first data along a tooth axis direction of the tooth. The method according to any one of claims 1 to 4.

6. arranging the central axis of the first data along a tooth axis direction of the tooth includes arranging the central axis of the first data at a center of the tooth when viewed from a direction from a crown to a root of the tooth. The method according to claim 5.

7. Furthermore, A step of overlaying second data, in which a plurality of plates are arranged, on the scan data; creating a third cross-sectional curve and a fourth cross-sectional curve that indicate an outline line of the scan data, with the deleted portion sandwiched between the third cross-sectional curve and the fourth cross-sectional curve, in each cross-section of the scan data cut by the plurality of plates of the second data; extending the third cross-section curve and the fourth cross-section curve in a direction to compensate for the deleted portion of the scan data in each cross-section of the scan data cut by the plurality of plates of the second data; Including, the step of restoring the tooth edge portion includes restoring the tooth edge portion based on the extended first cross-sectional curve, the extended second cross-sectional curve, the extended third cross-sectional curve, and the extended fourth cross-sectional curve; The method of claim 1.

8. The step of restoring the tooth edge portion includes: Calculating a first intersection point where the extended first cross-section curve and the extended second cross-section curve intersect in each cross-section of the scan data cut by the plurality of plates of the first data; Calculating a second intersection point where the extended third cross-section curve and the extended fourth cross-section curve intersect in each cross-section of the scan data cut by the plurality of plates of the second data; creating an intersection line based on the calculated first intersection point and second intersection point; Reconstructing the tooth edge portion based on the intersection line; having The method according to claim 7.

9. Furthermore, extracting a boundary line surrounding the deleted portion from the scan data; Restoring the tooth edge portion based on the intersection line includes creating shape data from the boundary line to the intersection line. The method according to claim 8.

10. The first data includes a central axis along which the plates intersect, The step of overlaying the first data on the scan data includes arranging the first data such that the central axis is aligned with a tooth axis direction of the tooth, The step of overlaying the second data on the scan data includes arranging the second data so that an arrangement direction of the plurality of plates intersects with a tooth axis direction of the teeth. The method according to any one of claims 7 to 9.

11. The plurality of plates in the second data are arranged at equal intervals. The method according to any one of claims 7 to 10.

12. Furthermore, a step of overlaying third data, in which a plurality of plates are arranged along a second direction different from a first direction in which the plurality of plates are arranged in the second data, on the scan data; creating a fifth cross-sectional curve and a sixth cross-sectional curve that indicate an outline line of the scan data, with the deleted portion sandwiched between the fifth cross-sectional curve and the sixth cross-sectional curve, in each of the cross-sections of the scan data cut by the plurality of plates of the third data; extending the fifth cross-sectional curve and the sixth cross-sectional curve in a direction to compensate for the deleted portion of the scan data in each cross-section of the scan data cut by the plurality of plates of the third data; Including, the step of restoring the tooth edge portion includes restoring the tooth edge portion based on the first extended cross-section curve, the second extended cross-section curve, the third extended cross-section curve, the fourth extended cross-section curve, the fifth extended cross-section curve, and the sixth extended cross-section curve. The method according to any one of claims 7 to 11.

13. The plurality of plates in the third data are arranged at equal intervals. The method of claim 12.

14. The number of the plurality of boards in the first data is 60 or more and 3500 or less. The method according to any one of claims 1 to 13.

15. The plurality of plates in the first data are arranged at equal intervals. The method according to any one of claims 1 to 14.

16. The tooth edge portion includes at least one of an edge portion of an abutment tooth, a cavity, a retention groove, or a dentition; The method according to any one of claims 1 to 15.

17. A program for causing a computer to execute the method according to any one of claims 1 to 16.

18. A computer-readable recording medium having recorded thereon a program for causing a computer to execute the method according to any one of claims 1 to 16.

19. A device for restoring the shape of a tooth edge portion changed by scanning, comprising: one or more processors; a memory storing instructions executable by said one or more processors; having The instruction: obtaining dental scan data; removing scan data of edge portions of the teeth from the scan data; A step of overlaying a first data set in which a plurality of plates are radially arranged on the scan data; creating a first cross-sectional curve and a second cross-sectional curve that indicate an outline line of the scan data, with the deleted portion sandwiched between the first cross-sectional curve and the second cross-sectional curve, in each cross-sectional surface of the scan data cut by the plurality of plates of the first data; Extending the first cross-section curve and the second cross-section curve in a direction to compensate for the deleted portion of the scan data in each cross-section of the scan data cut by the plurality of plates of the first data; restoring an edge portion of the tooth based on an extended first cross-section curve and an extended second cross-section curve in each cross-section of the scan data cut by the plurality of plates of the first data; 13. An apparatus comprising:

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