EP-4740899-A1 - METHOD, APPARATUS, AND RECORDING MEDIUM RECORDING INSTRUCTIONS FOR ALIGNING 3D DATA OF ORAL CAVITY WITH OCCLUSAL PLANE

EP4740899A1EP 4740899 A1EP4740899 A1EP 4740899A1EP-4740899-A1

Abstract

Disclosed is a technique for aligning three-dimensional data of an oral cavity to an occlusal plane. A method performed by an electronic device according to an aspect of the present disclosure may include the steps of: obtaining first data which is three-dimensional data for an oral cavity including a plurality of teeth; determining three-dimensional center coordinates of each of the plurality of teeth indicated by the first data; determining one or more target teeth among the plurality of teeth; determining one or more reference center points respectively corresponding to the one or more target teeth on an occlusal plane for aligning the plurality of teeth; and generating a transformation matrix for aligning the first data to the occlusal plane on the basis of three-dimensional center coordinates of each of the one or more target teeth and the one or more reference center points.

Inventors

LEE, SUNGHOON

Assignees

Medit Corp.

Dates

Publication Date: 20260513
Application Date: 20240705

Claims (20)

A method performed by an electronic device, the method comprising: obtaining first data corresponding to three-dimensional data for an oral cavity comprising a plurality of teeth; determining three-dimensional center coordinates of each of the plurality of teeth indicated by the first data; determining one or more target teeth among the plurality of teeth; determining one or more reference center points corresponding to the one or more target teeth, respectively, on an occlusal plane for aligning the plurality of teeth; and generating a transformation matrix for aligning the first data to the occlusal plane, based on the three-dimensional center coordinates of each of the one or more target teeth and the one or more reference center points.
The method of Claim 1, wherein the determining of the one or more target teeth among the plurality of teeth comprises: classifying each of the plurality of teeth as one of a first tooth group and a second tooth group; determining whether there is a first pair of teeth at positions corresponding to each other with reference to a midline of the oral cavity and belonging to the first tooth group; and determining whether there is a second pair of teeth at positions corresponding to each other with reference to the midline and belonging to the second tooth group.
The method of Claim 2, further comprising determining an identification number of each of the plurality of teeth, wherein the determining of whether there is the first pair of teeth and the determining of whether there is the second pair of teeth are based on the identification number of each of the plurality of teeth.
The method of Claim 2, wherein the determining of the one or more target teeth among the plurality of teeth comprises, in response to determination that both the first pair of teeth and the second pair of teeth exist, determining four teeth included in the first pair of teeth and the second pair of teeth as the one or more target teeth.
The method of Claim 3, wherein the determining of the one or more target teeth among the plurality of teeth further comprises when there are a plurality of pairs of teeth at positions corresponding to each other with reference to the midline among one or more teeth included in the first tooth group, determining, as the first pair of teeth, a pair of teeth comprising a tooth closest from the midline among the plurality of teeth at positions corresponding to each other with reference to the midline.
The method of Claim 3, wherein the determining of the one or more target teeth among the plurality of teeth further comprises when there are a plurality of pairs of teeth at positions corresponding to each other with reference to the midline among one or more teeth included in the second tooth group, determining, as the second pair of teeth, a pair of teeth comprising a tooth closest from the midline among the plurality of teeth at positions corresponding to each other with reference to the midline.
The method of Claim 2, wherein the generating of the transformation matrix comprises, in response to determination that both the first pair of teeth and the second pair of teeth exist, generating the transformation matrix so that two or more straight lines derived based on three-dimensional center coordinates of the four teeth align with corresponding straight lines on the occlusal plane.
The method of Claim 2, wherein the determining of the one or more target teeth among the plurality of teeth comprises, in response to determination that at least one of the first pair of teeth and the second pair of teeth does not exist, determining all of the plurality of teeth as the one or more target teeth.
The method of Claim 8, wherein the generating of the transformation matrix comprises, in response to determination that at least one of the first pair of teeth and the second pair of teeth does not exist, generating the transformation matrix so that three-dimensional center coordinates of each of the one or more target teeth are moved as close as possible to a corresponding reference center point of the occlusal plane and an oral cavity movement amount indicated by the first data is minimized.
The method of Claim 1, wherein the determining of the three-dimensional center coordinates of each of the plurality of teeth indicated by the first data comprises: generating, based on the first data, second data corresponding to two-dimensional data for the oral cavity; identifying each of the plurality of teeth from the second data; determining two-dimensional center coordinates of each of the plurality of teeth; and determining three-dimensional center coordinates of each of the plurality of teeth, based on the two-dimensional center coordinates.
The method of Claim 10, wherein the generating of the second data corresponding to the two-dimensional data for the oral cavity comprises: identifying a tooth area indicated by the first data, wherein the tooth area comprises the plurality of teeth; adding a color indicating a curvature to each point of the tooth area; and generating the second data, based on data of the tooth area in which the color is added, among the first data.
The method of Claim 11, wherein the determining of the two-dimensional center coordinates of each of the plurality of teeth comprises: identifying each of the plurality of teeth indicated by the second data; generating a plurality of bounding boxes corresponding to the plurality of teeth, respectively, wherein the plurality of boxes have a smallest quadrilateral shape comprising an area in which each of the plurality of teeth is positioned in the second data; and determining a center of each of the plurality of bounding boxes as two-dimensional center coordinates of a corresponding tooth.
The method of Claim 10, wherein the determining of the two-dimensional center coordinates of each of the plurality of teeth comprises applying the second data to a training model to obtain output data, wherein the output data identifies each of the plurality of teeth and indicates the two-dimensional center coordinates of each of the plurality of teeth.
The method of Claim 10, wherein the determining of the three-dimensional center coordinates of each of the plurality of teeth comprises: determining a plurality of first points which correspond to the two-dimensional center coordinates of each of the plurality of teeth and are on a plane identical or parallel to the occlusal plane; determining a plurality of second points on surfaces of the plurality of teeth, which correspond to the plurality of first points, wherein each of the plurality of second points is an intersection point between a straight line which is parallel to a normal line of the occlusal plane and passes through a corresponding first point and a surface of each of the plurality of teeth; and determining the plurality of second points as the three-dimensional center coordinates of each of the plurality of teeth.
The method of Claim 14, wherein the determining of the three-dimensional center coordinates of each of the plurality of teeth comprises: determining, based on the plurality of second points, a plurality of third points corresponding to cusp points of each of the plurality of teeth; and determining the plurality of third points as the three-dimensional center coordinates of each of the plurality of teeth.
The method of Claim 15, wherein the determining of the third point of each of the plurality of teeth comprises determining, as the third point of each of the plurality of teeth, a point at which a curvature has a maximum value among points obtained by moving the plurality of second points in a buccal direction and a lingual direction along the surface of each of the plurality of teeth.
The method of Claim 1, further comprising aligning the first data to the occlusal plane, based on the transformation matrix.
The method of Claim 1, further comprising: segmenting surfaces of a plurality of teeth indicated by the first data into one or more polygons; determining one or more first normal vectors for each of the one or more polygons; determining a second normal vector corresponding to the first data, based on the one or more first normal vectors; determining a third normal vector corresponding to a normal vector of the occlusal plane; and generating a rotation matrix for rotating the first data so that the second normal vector aligns with the third normal vector.
An electronic device comprising: one or more processors; and one or more memories in which instructions executed by the one or more processes are stored, wherein the one or more processors are configured to, when the instructions are executed by the one or more processors, execute the method according to any one of Claims 1 to 18.
A non-transitory computer-readable recording medium recording instructions which, when executed by one or more processors, cause the one or more processors to perform operations, wherein the instructions are configured to cause the one or more processors to execute the method according to any one of Claims 1 to 18.

Description

TECHNICAL FIELD The present disclosure relates to a technology for aligning three-dimensional data of an oral cavity with an occlusal plane. BACKGROUND The manufacture of dental prostheses and oral appliances requires accurate oral structure data of a patient. In the past, a scheme of making a model by taking an impression of an oral condition of patient by using a physical impression material was mainly used, but with development of technology, a scheme of obtaining a three-dimensional image of an internal structure of the oral cavity of the patient by using a three-dimensional oral scanner is being used. A three-dimensional scanner may project lasers and light rays from various angles, and measure the degree of reflection of the corresponding light ray so as to convert an accurate shape of an internal oral structure including teeth and gingiva into three-dimensional data. Based on three-dimensional data, prostheses, crowns, bridges, implants, orthodontic appliances, and the like can be designed and manufactured according to the oral condition of an individual patient by using a Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) system. When various processing based on three-dimensional data is performed to design an oral appliance, the three-dimensional data needs to be precisely aligned with an occlusal plane so that each processing procedure can be performed as intended. DISCLOSURE TECHNICAL PROBLEM A technical problem to be solved through at least one embodiment of the present disclosure provides a technology enabling three-dimensional data of an oral cavity to be precisely aligned with an occlusal plane. A technical problem to be solved through at least one embodiment of the present disclosure provides a technology enabling a transformation matrix for aligning three-dimensional data with an occlusal plane to be generated. A technical problem to be solved through at least one embodiment of the present disclosure provides a technology enabling three-dimensional data to be precisely aligned with an occlusal plane even though tooth pairs corresponding each other do not exist in the three-dimensional data. The technical problems of the present disclosure are not limited to the above-mentioned technical problems, and other unmentioned technical problems can be clearly understood by those skilled in the art of the present disclosure from the description below. TECHNICAL SOLUTION A method performed by an electronic device according to one aspect of the present disclosure may include: obtaining first data corresponding to three-dimensional data for an oral cavity comprising a plurality of teeth; determining three-dimensional center coordinates of each of the plurality of teeth indicated by the first data; determining one or more target teeth among the plurality of teeth; determining one or more reference center points corresponding to the one or more target teeth, respectively, on an occlusal plane for aligning the plurality of teeth; and generating a transformation matrix for aligning the first data to the occlusal plane, based on the three-dimensional center coordinates of each of the one or more target teeth and the one or more reference center points. According to one embodiment of the present disclosure, wherein the determining of the one or more target teeth among the plurality of teeth comprises: classifying each of the plurality of teeth as one of a first tooth group and a second tooth group; determining whether there is a first pair of teeth at positions corresponding to each other with reference to a midline of the oral cavity and belonging to the first tooth group; and determining whether there is a second pair of teeth at positions corresponding to each other with reference to the midline and belonging to the second tooth group. According to one embodiment of the present disclosure, the method further comprising determining an identification number of each of the plurality of teeth, wherein the determining of whether there is the first pair of teeth and the determining of whether there is the second pair of teeth are based on the identification number of each of the plurality of teeth. According to one embodiment of the present disclosure, wherein the determining of the one or more target teeth among the plurality of teeth comprises, in response to determination that both the first pair of teeth and the second pair of teeth exist, determining four teeth included in the first pair of teeth and the second pair of teeth as the one or more target teeth. According to one embodiment of the present disclosure, wherein the determining of the one or more target teeth among the plurality of teeth further comprises when there are a plurality of pairs of teeth at positions corresponding to each other with reference to the midline among one or more teeth included in the first tooth group, determining, as the first pair of teeth, a pair of teeth comprising a tooth closest from the midline among the