DETECTION APPARATUS, DETECTION METHOD, DETECTION PROGRAM, AND DETECTION SYSTEM

Abstract

To provide a technology capable of detecting an early contact position with high precision.SOLUTION: A detector 1 includes: an input interface 14 which inputs upper jaw dentition data showing a three-dimensional shape of an upper jaw dentition acquired by a three-dimensional scanner 2 when the upper and lower dentitions are in open state, a lower jaw dentition data showing a three-dimensional shape of the lower jaw dentition acquired by the three-dimensional scanner 2 when the upper and lower dentitions are opened, and occlusion data showing a three-dimensional shape of the upper and lower dentitions acquired by the three-dimensional scanner 2 when the upper and lower dentitions are in the occlusion state; and an arithmetic unit 11 which generates synthetic data showing the three-dimensional shape of the upper and lower dentitions in the occlusion state by matching the upper jaw dentition data and the lower jaw dentition data with the occlusion data as reference and detects the early contact position by updating at least one dentition data of the upper jaw dentition data and the lower jaw dentition data included in the synthetic data so that the upper and lower dentitions shift from the occlusion state to the opening state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a detection device, a detection method, a detection program, and a detection system for detecting a premature contact position where premature contact occurs when the upper and lower teeth occlude. [Background technology]

[0002] In clinical dentistry, it is important to know the premature contact position when the upper and lower teeth bite. The premature contact position is the position where the upper and lower teeth first come into contact when the upper and lower teeth bite. If there is a bias in the premature contact position between the upper and lower teeth, the frequency of chewing at the premature contact position increases, which can cause the jaw to become distorted and the body to lose balance, which can have a negative impact on health. Traditionally, in the field of dentistry, treatments such as grinding down the premature contact position have been performed to bring the entire upper and lower teeth into contact simultaneously in a balanced manner.

[0003] As a technique for detecting the early contact position, Patent Document 1 discloses a dental occlusion pressure measuring device that includes a sensor sheet on which a marking material is applied and which is bitten by a subject, and a computer that processes data indicating pressure detection points of the sensor sheet during biting. The dental occlusion pressure measuring device can detect the early contact position by detecting the tooth contact position and biting pressure using the sensor sheet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-279094 A Summary of the Invention [Problem to be solved by the invention]

[0005] According to the dental occlusal pressure measuring device disclosed in Patent Document 1, it is possible to detect the early contact position using a sensor sheet. However, since the subject must bite the sensor sheet when detecting the early contact position, the tooth contact position and the occlusal pressure may vary depending on the degree to which the subject bites the sensor sheet, and there is a risk that the early contact position cannot be detected with high accuracy.

[0006] The present disclosure has been made to solve such problems, and has an object to provide a technique capable of detecting the early contact position with high accuracy. [Means for solving the problem]

[0007] According to one example of the present disclosure, there is provided a detection device for detecting an early contact position where early contact occurs when the upper and lower teeth are in occlusion. The detection device includes an input unit to which maxillary teeth data showing the three-dimensional shape of the maxillary teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an open-mouth state, mandibular teeth data showing the three-dimensional shape of the mandibular teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an open-mouth state, and occlusion data showing the three-dimensional shape of the upper and lower teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an occlusal state; The upper jaw dentition data, the lower jaw dentition data, and the occlusion data are converted into three-dimensional data in a common coordinate system, and each of the upper jaw dentition data and the lower jaw dentition data is aligned with a corresponding portion of the occlusion data in the common coordinate system. By doing so, synthetic data is generated that shows the three-dimensional shape of the upper and lower dentition in an occlusal state, The upper and lower teeth are displaced from an occlusal state to an open state. The upper and lower jaw dentition data included in the synthetic data on the other hand The dentition data of Move it gradually away from the other dentition data and a calculation unit that detects the early contact position by updating the position of the early contact.

[0008] According to one embodiment of the present disclosure, a premature contact position where the upper and lower teeth make premature contact when they bite is calculated by a computer. The detection method includes, as a process executed by the computer, steps of acquiring maxillary dentition data showing the three-dimensional shape of the maxillary dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in an open-mouth state, mandibular dentition data showing the three-dimensional shape of the mandibular dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in an open-mouth state, and occlusion data showing the three-dimensional shapes of the upper and lower dentitions acquired by the three-dimensional scanner when the upper and lower dentitions are in an occlusal state; The upper jaw dentition data, the lower jaw dentition data, and the occlusion data are converted into three-dimensional data in a common coordinate system, and each of the upper jaw dentition data and the lower jaw dentition data is aligned with a corresponding portion of the occlusion data in the common coordinate system. By doing so, synthetic data is generated that shows the three-dimensional shape of the upper and lower dentition in an occlusal state, The upper and lower teeth are displaced from an occlusal state to an open state. The upper and lower jaw dentition data included in the synthetic data on the other hand The dentition data of Move it gradually away from the other dentition data and detecting an early touch location by updating the position of the early touch area so as to detect the early touch location.

[0009] According to one example of the present disclosure, there is provided a detection program for detecting an early contact position where early contact occurs when the upper and lower teeth are in occlusion. The detection program includes steps of acquiring, in a computer, maxillary teeth data showing a three-dimensional shape of the upper jaw teeth acquired by a three-dimensional scanner when the upper and lower teeth are in an open-mouth state, mandibular teeth data showing a three-dimensional shape of the lower jaw teeth acquired by a three-dimensional scanner when the upper and lower teeth are in an open-mouth state, and occlusion data showing the three-dimensional shapes of the upper and lower teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an occlusal state; The upper jaw dentition data, the lower jaw dentition data, and the occlusion data are converted into three-dimensional data in a common coordinate system, and each of the upper jaw dentition data and the lower jaw dentition data is aligned with a corresponding portion of the occlusion data in the common coordinate system. By doing so, synthetic data is generated that shows the three-dimensional shape of the upper and lower dentition in an occlusal state, The upper and lower teeth are displaced from an occlusal state to an open state. The upper and lower jaw dentition data included in the synthetic data on the other hand The dentition data of Move it gradually away from the other dentition data and detecting an early contact position by updating the position of the early contact point.

[0010] According to one example of the present disclosure, there is provided a detection system for detecting an early contact position where early contact occurs when the upper and lower teeth are in occlusion. The detection system includes a three-dimensional scanner for acquiring three-dimensional data showing the three-dimensional shapes of the upper and lower teeth, and a detection device for detecting the early contact position based on the three-dimensional data acquired by the three-dimensional scanner. The detection device includes an input unit to which upper jaw teeth data showing the three-dimensional shape of the upper jaw teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an open-mouth state, lower jaw teeth data showing the three-dimensional shape of the lower jaw teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an open-mouth state, and occlusion data showing the three-dimensional shape of the upper and lower teeth acquired by the three-dimensional scanner when the upper and lower teeth are in an occlusal state are inputted; The upper jaw dentition data, the lower jaw dentition data, and the occlusion data are converted into three-dimensional data in a common coordinate system, and each of the upper jaw dentition data and the lower jaw dentition data is aligned with a corresponding portion of the occlusion data in the common coordinate system. By doing so, synthetic data is generated that shows the three-dimensional shape of the upper and lower dentition in an occlusal state, The upper and lower teeth are displaced from an occlusal state to an open state. The upper and lower jaw dentition data included in the synthetic data on the other hand The dentition data of Move it gradually away from the other dentition data and a calculation unit that detects the early contact position by updating the position of the early contact. Effect of the Invention

[0011] According to the present disclosure, a user can detect the early contact position with high accuracy by measuring the three-dimensional shape of the upper and lower dentition using a three-dimensional scanner. [Brief description of the drawings]

[0012] [Figure 1] 1A to 1C are diagrams illustrating application examples of a detection system and a detection device according to an embodiment. [Diagram 2] 1 is a block diagram showing a hardware configuration of a detection system and a detection device according to an embodiment. [Diagram 3] 1A and 1B are diagrams illustrating an overview of an early contact position detection process executed by a detection device according to an embodiment. [Figure 4] FIG. 11 is a diagram for explaining composite data. [Diagram 5] 1A and 1B are diagrams illustrating an overview of an early contact position detection process executed by a detection device according to an embodiment. [Figure 6] 10 is a flowchart illustrating an example of a detection process executed by a detection device according to an embodiment. [Figure 7] 13 is a diagram for explaining a distribution rate used by a detection device according to a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Embodiment> The embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0014] [Example of application] An application example of a detection system 10 and a detection device 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an application example of a detection system 10 and a detection device 1 according to an embodiment.

[0015] 1, a detection system 10 according to an embodiment includes a detection device 1 and a three-dimensional scanner 2. A user can obtain three-dimensional data indicating the shapes of a plurality of objects in the oral cavity by scanning the oral cavity of a subject using the three-dimensional scanner 2. The detection device 1 is communicatively connected to the three-dimensional scanner 2, and processes the three-dimensional data obtained by the three-dimensional scanner 2.

[0016] The "user" may be anyone who acquires 3D data of an object such as a tooth using the 3D scanner 2, such as a dentist or other practitioner, a dental assistant, a professor or student at a dental school, a dental technician, a manufacturer's engineer, or a worker at a manufacturing plant. The "subject" may be anyone who can be scanned by the 3D scanner 2, such as a patient at a dental clinic or a subject at a dental school.

[0017] The "object" to be scanned may be anything that can be scanned by the three-dimensional scanner 2, such as the upper and lower teeth and gums in the oral cavity. "Upper and lower teeth" includes the upper and lower teeth. When the mouth is open, the upper and lower teeth are separated from each other. When the mouth is occluded, the upper and lower teeth are in contact with each other.

[0018] The three-dimensional scanner 2 is a so-called intraoral scanner (IOS) capable of optically imaging the inside of the oral cavity of a subject by a confocal method, a triangulation method, or the like. Specifically, the three-dimensional scanner 2 scans an object in the oral cavity, and acquires, as three-dimensional data, position information (coordinates of each axis in the vertical, horizontal, and height directions) of each of a point cloud (multiple points) indicating the surface shape of the object to be scanned (object), using an optical sensor or the like. In other words, the three-dimensional data is position data (IOS data) including position information of each of the point clouds constituting the surface of an object placed in a certain coordinate space.

[0019] The three-dimensional data that can be acquired by the three-dimensional scanner 2 scanning the maxillary dentition when the upper and lower dentition are in an open-mouth state includes position information of at least one tooth included in the maxillary dentition and each of the points constituting the surface of the gums supporting the at least one tooth. Such three-dimensional data showing the three-dimensional shape of the maxillary dentition in an open-mouth state is also referred to as "maxillary dentition data."

[0020] The three-dimensional data that can be acquired by the three-dimensional scanner 2 scanning the lower jaw dentition when the upper and lower teeth are in an open mouth state includes position information of at least one tooth included in the lower jaw dentition and each of the points constituting the surface of the gums supporting the at least one tooth. Such three-dimensional data showing the three-dimensional shape of the lower jaw dentition in the open mouth state is also referred to as "mandibular dentition data".

[0021] The three-dimensional data that can be obtained by the three-dimensional scanner 2 scanning the upper and lower jaw dentition when the upper and lower teeth are in an occlusal state includes position information of each of the point groups that constitute the surfaces of at least one tooth included in the upper jaw dentition, the gums supporting the at least one upper jaw tooth, at least one tooth included in the lower jaw dentition, and the gums supporting the at least one lower jaw tooth. Such three-dimensional data that shows the three-dimensional shapes of the upper and lower teeth in an occlusal state is also called "occlusion data."

[0022] The detection device 1 generates a two-dimensional image showing a two-dimensional object seen from an arbitrary viewpoint based on the three-dimensional data of the object acquired by the three-dimensional scanner 2. Such a two-dimensional image is generated by processing or editing the three-dimensional data, and is also called a "rendered image." The detection device 1 displays the generated rendering image on the display 3, thereby enabling the user to see the surface of the intraoral object seen from an arbitrary viewpoint.

[0023] According to the detection system 10 as described above, for example, a user can scan the upper and lower dentition in the oral cavity using the three-dimensional scanner 2, and have a rendering image showing the upper and lower dentition in two dimensions as viewed from any viewpoint displayed on the display 3.

[0024] Conventionally, an occlusal paper is used as a method for detecting the position of early contact when the upper and lower teeth bite. The occlusal paper is a sheet-like paper with a red or blue paint transferred onto its surface. When a subject bites with the occlusal paper between the upper and lower teeth, a part of the occlusal surface is colored according to the bite. By checking the coloring pattern of such an occlusal surface, a dentist or the like can detect the position of early contact. For example, it can be said that a darkly colored part of the occlusal surface is more likely to be in early contact between the upper and lower teeth than a lightly colored part.

[0025] Dentists and the like can detect the early contact position to some extent by using the above-mentioned articulating paper. However, since the subject must bite the articulating paper when detecting the early contact position, the tooth contact position and the bite pressure may vary depending on the degree to which the subject bites the articulating paper, and there is a risk that the early contact position cannot be detected with high accuracy.

[0026] Therefore, in the detection system 10 according to the embodiment, the detection device 1 is configured to detect the early contact position based on the three-dimensional data of the intraoral object acquired by the three-dimensional scanner 2. The detection process of the early contact position executed by the detection device 1 will be specifically described below.

[0027] [Hardware configuration of the detector] The hardware configuration of the detection system 10 and the detection device 1 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the hardware configuration of the detection system 10 and the detection device 1 according to the embodiment. The detection device 1 may be realized, for example, by a general-purpose computer or a computer dedicated to the detection system 10.

[0028] As shown in FIG. 2, the detection device 1 includes, as its main hardware elements, a processing unit 11, a memory 12, a storage device 13, a scanner interface 14, a display interface 15, a peripheral device interface 16, a media reading device 17, and a communication device 18.

[0029] The arithmetic device 11 has the function of a "arithmetic unit" and is composed of a computer such as a processor. The processor is composed of, for example, a microcontroller, a central processing unit (CPU), or a micro-processing unit (MPU). The processor has a function of executing various processes by executing a program, and some or all of these functions may be implemented using a dedicated hardware circuit such as an application specific integrated circuit (ASIC), a graphics processing unit (GPU), or a field-programmable gate array (FPGA). The "processor" is not limited to a processor in the narrow sense that executes processes in a stored program manner such as a CPU or an MPU, but may include a hardwired circuit such as an ASIC or an FPGA. For this reason, the processor can also be read as a processing circuitry in which processing is defined in advance by computer-readable code and / or a hardwired circuit. The processor may be composed of one chip or multiple chips. Furthermore, the processor and related processing circuits may be composed of multiple computers interconnected by wire or wirelessly via a local area network or a wireless network. The processor and associated processing circuitry may be configured as a cloud computer that performs computations remotely based on input data and outputs the results of the computations to other devices at remote locations.

[0030] The memory 12 provides a storage area for storing program codes or work memory when the processor of the arithmetic device 11 executes various programs. The memory 12 may be one or more non-transitory computer readable media. Examples of the memory 12 include volatile memories such as dynamic random access memory (DRAM) and static random access memory (SRAM), and non-volatile memories such as read only memory (ROM) and flash memory.

[0031] The storage device 13 provides a storage area for storing various programs that can be read and executed by the processor of the arithmetic device 11, and various data. The storage device 13 may be one or more computer readable storage media. Examples of the storage device 13 include storage devices such as a hard disk drive (HDD) and a solid state drive (SSD).

[0032] The storage device 13 stores the detection program 100. The detection program 100 is a program in which the contents of a detection process for detecting an early contact position are described based on three-dimensional data of an object in the oral cavity acquired by the three-dimensional scanner 2, and can be read and executed by the arithmetic device 11. The detection program 100 may be inputted and executed by a user using the keyboard 4 and mouse 5, may be read from the recording medium 20 by the media reading device 17, or may be acquired by the communication device 18 from another device such as a server via a network.

[0033] The scanner interface 14 has the function of an "input unit" and is an interface for connecting the three-dimensional scanner 2. The scanner interface 14 may be composed of an input circuitry. The scanner interface 14 realizes input and output of data between the detection device 1 and the three-dimensional scanner 2. The detection device 1 and the three-dimensional scanner 2 are connected via a wired connection using a cable, or wirelessly (WiFi, Bluetooth (registered trademark), etc.).

[0034] The display interface 15 is an interface for connecting the display 3 and realizes input and output of data between the detection device 1 and the display 3 .

[0035] The peripheral device interface 16 is an interface for connecting peripheral devices such as the keyboard 4 and mouse 5, and realizes input and output of data between the detection device 1 and the peripheral devices.

[0036] The media reader 17 reads data stored in the recording medium 20 and writes data to the recording medium 20. The recording medium 20 is a non-transitory and tangible computer readable storage medium, and may be in any form capable of recording various data, such as a CD (Compact Disc), a DVD (Digital Versatile Disc), or a USB (Universal Serial Bus) memory. In the embodiment, the recording medium 20 can store a detection program 100, and the arithmetic device 11 can execute the detection program 100 read from the recording medium 20.

[0037] The communication device 18 transmits and receives data to and from an external device via wired or wireless communication. For example, the communication device 18 can transmit data indicating the detection result of the early contact position to the server device by being communicatively connected to an in-hospital server or an external server (e.g., a cloud server) via a wired connection using a cable or wirelessly (WiFi, Bluetooth (registered trademark), etc.).

[0038] [Detection process] An overview of the early contact position detection process executed by the detection device 1 according to the embodiment will be described with reference to FIGS.

[0039] FIG. 3 is a diagram showing an outline of the detection process of the early contact position executed by the detection device 1 according to the embodiment. As shown in FIG. 3, in STEP 1, the user acquires three-dimensional data of the upper and lower dentition of the subject. Specifically, the user opens the upper and lower dentition of the subject and scans mainly the occlusal surface and the side surface of the upper dentition using the three-dimensional scanner 2. This allows the three-dimensional scanner 2 to acquire upper dentition data showing the three-dimensional shape of the upper dentition. The upper dentition data is output to the detection device 1 via the scanner interface 14. The detection device 1 can generate a rendering image showing the two-dimensional upper dentition from an arbitrary viewpoint based on the acquired upper dentition data.

[0040] The user also opens the upper and lower teeth of the subject and manually scans mainly the occlusal surface and sides (buccal surface and lingual surface) of the mandibular teeth using the three-dimensional scanner 2. This allows the three-dimensional scanner 2 to acquire mandibular teeth data showing the three-dimensional shape of the mandibular teeth. The mandibular teeth data is output to the detection device 1 via the scanner interface 14. Based on the acquired mandibular teeth data, the detection device 1 can generate a rendering image showing the two-dimensional mandibular teeth viewed from any viewpoint.

[0041] Furthermore, the user places the upper and lower teeth of the subject in an occlusal state and manually scans mainly the side (buccal) surface of the upper and lower teeth in the occlusal state. This allows the three-dimensional scanner 2 to obtain occlusal data indicating the three-dimensional shape of the upper and lower teeth. The occlusal data is output to the detection device 1 via the scanner interface 14. Based on the obtained occlusal data, the detection device 1 can generate a rendering image indicating the upper and lower teeth in a two-dimensional occlusal state as viewed from any viewpoint.

[0042] As described above, the maxillary dentition data and the mandibular dentition data are acquired separately, so that the rendering image based on the maxillary dentition data and the rendering image based on the mandibular dentition data can be freely changed to the open state or occlusal state, it is necessary to combine the maxillary dentition data and the mandibular dentition data according to the upper and lower dentition in the occlusal state. Therefore, in STEP 2, the detection device 1 generates composite data showing the three-dimensional shape of the upper and lower dentition in the occlusal state by combining the maxillary dentition data and the mandibular dentition data based on the occlusal data.

[0043] Specifically, the detection device 1 converts the maxillary dentition data, mandibular dentition data, and occlusion data, each of which is acquired separately, into three-dimensional data in a common coordinate system. For example, the detection device 1 converts each of the coordinate systems of the maxillary dentition data and mandibular dentition data to match the coordinate system of the occlusion data. Alternatively, the detection device 1 converts each of the coordinate systems of the maxillary dentition data, mandibular dentition data, and occlusion data to match a predetermined common coordinate system.

[0044] Then, the detection device 1 aligns the maxillary dentition data in the common coordinate system with a portion of the occlusion data in the common coordinate system that corresponds to the maxillary dentition. More specifically, the detection device 1 aligns the three-dimensional data of the point cloud corresponding to the maxillary dentition data including the marginal gingiva with the three-dimensional data of the point cloud corresponding to the maxillary dentition including the marginal gingiva in the occlusion data. At this time, the detection device 1 determines the three-dimensional data position of each point of the maxillary dentition data including the marginal gingiva for each point of the occlusion data including the marginal gingiva using a portion near the center in the vertical direction of the maxillary dentition data, for example, the gingival margin (boundary portion U shown in FIG. 3) which is the boundary portion between the teeth and the gingiva as a marker. The detection device 1 may determine the three-dimensional data position of each point of the maxillary dentition data including the marginal gingiva so that the error between each point of the occlusion data including the marginal gingiva is minimized, using a portion having a characteristic shape with large changes in unevenness in the maxillary dentition, not limited to the boundary portion U between the teeth and the gingiva, as a marker.

[0045] Moreover, the detection device 1 aligns the mandibular dentition data in the common coordinate system with a portion of the occlusion data in the common coordinate system that corresponds to the mandibular dentition. More specifically, the detection device 1 aligns the three-dimensional data of the point cloud corresponding to the mandibular dentition data including the peripheral gingiva with the three-dimensional data of the point cloud corresponding to the mandibular dentition including the peripheral gingiva in the occlusion data. At this time, the detection device 1 determines the three-dimensional data position of each point of the mandibular dentition data including the peripheral gingiva for each point of the occlusion data including the peripheral gingiva using a portion near the center in the vertical direction of the mandibular dentition data, for example, the gingival margin (boundary portion L shown in FIG. 3) which is the boundary portion between the teeth and the gingiva as a landmark. The detection device 1 may determine the three-dimensional data position of each point of the mandibular dentition data including the peripheral gingiva so that the error between each point of the occlusion data including the peripheral gingiva is minimized, using a portion having a characteristic shape with large changes in unevenness in the mandibular dentition, not limited to the boundary portion L between the teeth and the gingiva, as a landmark.

[0046] The composite data generated in STEP 2 uses the maxillary dentition data and the mandibular dentition data acquired separately to configure three-dimensional data of the upper and lower dentitions in an occlusal state. Therefore, the detection device 1 can update the maxillary dentition data so that the upper and lower dentitions in the rendering image change from an occlusal state to an open-mouth state. For example, the detection device 1 can update the height coordinate of any point included in the maxillary dentition data to the maxillary side, thereby moving the arbitrary point away from a point included in the mandibular dentition data. The detection device 1 can also update the mandibular dentition data so that the upper and lower dentitions in the rendering image change from an occlusal state to an open-mouth state. For example, the detection device 1 can update the height coordinate of any point included in the mandibular dentition data to the maxillary side, thereby moving the arbitrary point away from a point included in the maxillary dentition data. At each timing when such data is updated, the detection device 1 can generate a rendering image showing the two-dimensional upper and lower dentitions seen from an arbitrary viewpoint and display it on the display 3, thereby allowing the user to see the upper and lower dentitions changing from an occlusal state to an open-mouth state.

[0047] As described in STEP 1, the maxillary dentition data including the marginal gingiva and the mandibular dentition data including the marginal gingiva are aligned with the occlusion data including the marginal gingiva so that the error between each point is minimized. However, the maxillary dentition data and the mandibular dentition data are three-dimensional data of the dentition in the open mouth state, whereas the occlusion data are three-dimensional data of the dentition in the occlusion state. In the occlusion state, the maxillary dentition and the maxillary dentition are in contact with each other on the occlusion surface, so that the maxillary dentition and the maxillary dentition apply a load to each other, whereas in the open mouth state, the maxillary dentition and the maxillary dentition are not in contact with each other, so that the maxillary dentition and the maxillary dentition do not apply a load to each other.

[0048] Specifically, a load is applied to the maxillary dentition from the mandibular dentition, so that the roots of the maxillary teeth apply pressure to the periodontal ligament. As a result, the distance between the gum line (boundary part U shown in FIG. 3) and the tip of the maxillary tooth is different between the maxillary dentition data and the occlusion data. Specifically, the distance between the gum line and the tip of the maxillary tooth is longer in the maxillary dentition data than in the occlusion data. In other words, an arbitrary point corresponding to the maxillary dentition in the occlusion data acquired in an occlusion state is moved in the direction where the maxillary gingiva is located more than a corresponding point in the maxillary dentition data acquired in an open mouth state.

[0049] Furthermore, since the load from the maxillary dentition is applied to the mandibular dentition, the roots of the mandibular teeth apply pressure to the periodontal ligament. Therefore, the mandibular dentition data and the occlusion data have different distances between the gingival margin (boundary portion L shown in FIG. 3) and the tips of the mandibular teeth. Specifically, the mandibular dentition data has a longer distance between the gingival margin and the tips of the mandibular teeth than the occlusion data. In other words, an arbitrary point corresponding to the mandibular dentition in the occlusion data acquired in an occlusion state is moved in the direction where the mandibular gingiva is located, more than a corresponding point in the mandibular dentition data acquired in an open mouth state. As a result, the tips of the maxillary teeth and the tips of the mandibular teeth may intersect in the maxillary dentition data and the mandibular dentition data after alignment based on the occlusion data.

[0050] In this way, when focusing on the same points, there may be some positional deviation between each point corresponding to the occlusion data acquired in the occlusal state and each point corresponding to the maxillary dentition data and the mandibular dentition data acquired in the open mouth state. In the actual upper and lower dentition, the maxillary dentition cannot physically be located closer to the mandibular side than the mandibular dentition, but in the synthetic data generated in STEP 3, the tips of the maxillary teeth and the mandibular teeth may cross, so that the points corresponding to the maxillary dentition data may be located closer to the mandibular side than the points corresponding to the mandibular dentition data.

[0051] The synthetic data will be specifically described with reference to FIG. 4. FIG. 4 is a diagram for explaining synthetic data. FIG. 4(A) shows a rendering image showing the side of upper and lower teeth rows generated based on synthetic data. As shown in FIG. 4(A), it is assumed that the teeth rows are cut in the vertical direction in the rendering image of the synthetic data. In addition, in the cross section of the upper and lower teeth rows, the portion where the upper jaw teeth row corresponding to the upper jaw teeth row data and the lower jaw teeth row corresponding to the lower jaw teeth row data overlap is shown as region S.

[0052] Fig. 4(B) shows an enlarged view of a portion of the rendering image of the synthetic data that includes the region S. As shown in the region S in Fig. 4(B), although this is physically impossible in the actual upper and lower dentition, in the data, a point corresponding to the upper jaw dentition data may be located closer to the lower jaw than a point corresponding to the lower jaw dentition data.

[0053] Fig. 4(C) shows the upper and lower teeth viewed from the bottom side (mandibular side) in the rendering image of the composite data. As shown in Fig. 4(C), in the region S, the point corresponding to the upper teeth data is located closer to the mandibular side than the point corresponding to the mandibular teeth data, so that the teeth included in the upper teeth appear to protrude beyond the mandibular teeth. Hereinafter, such a protruding portion is also referred to as a protruding portion P.

[0054] The detection device 1 updates at least one of the maxillary dentition data and the mandibular dentition data so that the upper and lower dentitions in the rendering image are displaced from an occlusal state to an open state, and detects an early contact position depending on whether or not a protrusion P as shown in Figure 4(C) exists at the time of the update.

[0055] For example, Fig. 5 is a diagram showing an outline of the detection process of the early contact position executed by the detection device 1 according to the embodiment. As shown in Fig. 5, in STEP 3 following STEP 2 in Fig. 3, the detection device 1 detects the early contact position by updating the composite data. Specifically, before updating the composite data, some points corresponding to the upper jaw dentition data are located closer to the mandibular side than points corresponding to the mandibular dentition data. Therefore, in a rendering image in which the upper and lower teeth are viewed from the bottom side (the side opposite to the surface of the teeth of the lower teeth, the mandibular side), a plurality of protruding parts P1 to P3 are shown in which the teeth included in the upper jaw dentition protrude beyond the mandibular dentition.

[0056] When the detection device 1 updates the composite data so as to displace the upper and lower teeth from an occlusal state to an open state, each point corresponding to the upper jaw teeth data is separated from each point corresponding to the lower jaw teeth data. For example, in a rendering image in which the upper and lower teeth after the first update are viewed from the bottom side, only the protrusions P1 and P2 of the protrusions P1 to P3 before the update remain. Furthermore, the protrusion areas of the protrusions P1 and P2 after the first update are smaller than those of the protrusions P1 and P2 before the update. As a result, by updating the composite data, the detection device 1 can detect that the points corresponding to the upper jaw teeth data corresponding to the protrusions P3 and P4 are no longer in contact with the points corresponding to the lower jaw teeth data. Furthermore, by updating the composite data, the detection device 1 can detect that the areas of contact between the points corresponding to the upper jaw teeth data corresponding to the protrusions P1 and P2 and the points corresponding to the lower jaw teeth data have become smaller.

[0057] When the detection device 1 further updates the composite data so as to displace the upper and lower teeth from the occlusal state to the open state, the points corresponding to the upper and lower teeth data become further apart from the points corresponding to the lower and upper teeth data. For example, in a rendering image of the upper and lower teeth after the second update viewed from the bottom side, only the protrusion P1 of the protrusions P1 and P2 after the first update remains. Furthermore, the protrusion area of ​​the protrusion P1 after the second update is smaller than that of the protrusion P1 before the update. Thus, by updating the composite data, the detection device 1 can detect that the point corresponding to the upper and lower teeth data corresponding to the protrusion P1 is no longer in contact with the point corresponding to the lower and upper teeth data. Furthermore, by updating the composite data, the detection device 1 can detect that the area of ​​contact between the point corresponding to the upper and lower teeth data corresponding to the protrusion P2 and the point corresponding to the lower and upper teeth data has become smaller.

[0058] In this way, when the composite data is updated so that the upper and lower teeth are displaced from an occlusal state to an open state, the detection device 1 can detect the portion of the upper and lower teeth where the upper and lower teeth are in contact until the end (protrusion P2 in the example of Figure 5) as the early contact position.

[0059] The detection device 1 can also calculate the amount by which the point corresponding to the early contact position protrudes from other points based on the update amount of the composite data, i.e., the update amount of at least one of the maxillary dentition data and the mandibular dentition data. For example, in the example of FIG. 5, if it is assumed that the protruding portion P2 disappears when the update data is updated for the third time, the detection device 1 can predict that the protruding portion P2 protrudes from the protruding portions P3 and P4 by the sum of the first update amount, the second update amount, and the third update amount, and can further predict that the protruding portion P2 protrudes from the protruding portion P1 by the sum of the second update amount and the third update amount. The amount of one update can be arbitrarily set by the user, and is, for example, 0.1 mm to 0.3 mm.

[0060] Regarding the direction of movement of a point corresponding to at least one of the maxillary dentition data and the mandibular dentition data, the detection device 1 may move the point corresponding to the at least one of the dentition data in any direction so long as the direction is such that the upper and lower dentitions change from an occlusal state to an open state.

[0061] For example, the detection device 1 may update the height coordinate of a point corresponding to the maxillary dentition data toward the maxillary side, so that the upper and lower dentitions appear to shift from an occluded state to an open-mouth state in the rendering image. The detection device 1 may also update the height coordinate of a point corresponding to the mandibular dentition data toward the mandibular side, so that the upper and lower dentitions appear to shift from an occluded state to an open-mouth state in the rendering image.

[0062] Alternatively, the detection device 1 may update at least one of the maxillary dentition data and the mandibular dentition data based on jaw movement data estimated based on the positions of the upper and lower dentitions in an occluded state. Specifically, the detection device 1 may predict the movements of the upper and lower jaws based on the maxillary dentition data and the mandibular dentition data included in the composite data. Then, the detection device 1 may update at least one of the maxillary dentition data and the mandibular dentition data based on the predicted jaw movement, thereby making the upper and lower teeth appear to be displaced from an occluded state to an open state in the rendering image.

[0063] Furthermore, the detection device 1 may update at least one of the maxillary dentition data and the mandibular dentition data based on the jaw movement data measured for the maxilla and the mandible. Specifically, the detection device 1 may acquire jaw movement data of the subject that is measured in advance while the subject wears a jig or the like. Then, the detection device 1 may update at least one of the maxillary dentition data and the mandibular dentition data based on the acquired jaw movement data, thereby making the upper and lower dentition appear to be displaced from an occluded state to an open state in the rendering image.

[0064] Furthermore, the detection device 1 may update at least one of the upper and lower teeth data based on a predetermined average jaw movement data. Specifically, the detection device 1 may obtain an average value of the jaw movement data of a plurality of people in advance. Such average values ​​of the jaw movement data may be distinguished according to gender or age. The detection device 1 may update at least one of the upper and lower teeth data based on the average value of the obtained jaw movement data, thereby making the upper and lower teeth appear to be displaced from an occluded state to an open state in the rendering image.

[0065] Furthermore, the detection device 1 may correct various types of jaw movement data as described above based on the check result of the occlusion of the upper and lower teeth using an articulation paper, and update at least one of the upper and lower teeth data based on the corrected jaw movement data. For example, the detection device 1 may correct the jaw movement data based on the coloring pattern (color that changes according to biting force) on the occlusal surface that appears when the subject bites with an articulation paper between the upper and lower teeth, so that the upper and lower teeth are separated in a portion (for example, a portion with a dark color) where the upper and lower teeth are likely to be in early contact with each other.

[0066] In this way, the detection device 1 can correct the jaw movement data based on the results of checking the occlusion of the upper and lower teeth using articulation paper, thereby updating at least one of the upper and lower teeth data to more closely resemble the jaw movement of the subject.

[0067] [Detection device processing flow] The flow of the early contact position detection process executed by the detection device 1 will be described with reference to Fig. 6. Fig. 6 is a flowchart for explaining an example of the detection process executed by the detection device 1 according to the embodiment. The detection device 1 (the calculation device 11) is capable of executing the detection process shown in Fig. 6 by executing the detection program 100. Note that in Fig. 6, "S" is used as an abbreviation for "STEP".

[0068] As shown in FIG. 6, the detection device 1 acquires the upper jaw dentition data, the lower jaw dentition data, and the occlusion data, each of which is acquired separately by the three-dimensional scanner 2 (S1). The detection device 1 generates composite data showing the three-dimensional shape of the upper and lower teeth in an occlusal state by combining the upper jaw dentition data and the lower jaw dentition data with the occlusion data (S2). When a rendering image is generated based on the composite data thus generated, as shown in FIG. 4, the teeth included in the upper jaw dentition may appear to protrude beyond the lower jaw dentition. In such a case, there is a possibility that an early contact position exists. The detection device 1 may acquire the composite data from another device. The other device may be another detection device 1, and the detection device 1 may acquire the composite data generated by the other detection device 1 from the other detection device 1. The other device may be a server device (cloud-type server device) that accumulates and stores the composite data collected from at least one other detection device 1, and the detection device 1 may acquire the composite data collected by the server device from the server device.

[0069] The detection device 1 updates at least one of the upper and lower jaw teeth data included in the composite data so that the upper and lower teeth in the rendering image are displaced from an occlusal state to an open state (S3). The amount of update per time in this case can be set arbitrarily by the user, and is, for example, 0.1 mm to 0.3 mm. As a result, in the rendering image based on the composite data, the upper and lower jaw teeth are separated by 0.1 mm to 0.3 mm for each update.

[0070] The detection device 1 determines whether the upper jaw dentition and the lower jaw dentition are in contact with each other in the updated composite data (S4). If the upper jaw dentition and the lower jaw dentition are in contact with each other (YES in S4), the detection device 1 executes the process of S3 again to update at least one of the upper jaw dentition data and the lower jaw dentition data again so that the upper and lower teeth in the rendering image are displaced from an occlusal state to an open mouth state. As a result, the upper jaw dentition and the lower jaw dentition are further separated by 0.1 mm to 0.3 mm in the rendering image based on the composite data. Thereafter, the detection device 1 executes the process of S4 again to determine whether the upper jaw dentition and the lower jaw dentition are in contact with each other in the updated composite data.

[0071] If the upper and lower teeth are not in contact (NO in S4), the detection device 1 identifies the contact position between the upper and lower teeth that was in contact until the end (just before updating) as an early contact position (S5). The detection device 1 stores three-dimensional data of at least one point corresponding to the identified early contact position in the memory 12 or the storage device 13 (S6), and ends this process.

[0072] As described above, the detection device 1 can detect the premature contact position by using the maxillary dentition data, mandibular dentition data, and occlusion data acquired by the three-dimensional scanner 2. This eliminates the need for the subject to occlude on an articulating paper, and therefore the dental contact position and occlusal pressure do not vary according to the subject's degree of occlusion, allowing the user to use the detection device 1 to detect the premature contact position with high accuracy.

[0073] <Modification> The present disclosure is not limited to the above-described embodiment, and various modifications and applications are possible. Modifications that can be applied to the present disclosure will be described below.

[0074] Fig. 7 is a diagram for explaining the deviation rate used by the detection device 1 according to the modified example. Fig. 7 (A1) to (D1) show rendering images based on composite data when the deviation of the contact position between the upper and lower teeth is normal. Fig. 7 (A2) to (D2) show rendering images based on composite data when the deviation of the contact position between the upper and lower teeth is abnormal.

[0075] As shown in Figs. 7(A1)-(D1) and Fig. 7(A2)-(D2), the detection device 1 updates at least one of the maxillary dentition data and the mandibular dentition data in a time series at every predetermined period so that the upper and lower dentitions in the rendering image change from an occlusal state to an open state. The detection device 1 detects the bias of the contact area between the maxillary dentition and the mandibular dentition at every predetermined period while updating at least one of the dentition data. Hereinafter, the bias of the contact area is also referred to as "bias distribution rate". That is, the detection device 1 calculates the bias rate at every predetermined period, which is the timing for updating the composite data.

[0076] The detection device 1 judges whether the maldistribution rate calculated for each predetermined period is equal to or greater than a preset threshold. When the maldistribution rate calculated for each predetermined period is equal to or greater than the threshold, the detection device 1 judges that there is a maldistribution in the contact area between the upper and lower jaw teeth, and executes an abnormality process. For example, as the abnormality process, the detection device 1 may notify the user that the maldistribution in the contact area between the upper and lower jaw teeth is abnormal using the display 3 or the like, may notify the user of the numerical value of the maldistribution rate using the display 3 or the like, or may notify the user of a level (e.g., a level divided into five stages) corresponding to the numerical value of the maldistribution rate using the display 3 or the like.

[0077] 7(A1)-(D1), the detection device 1 determines that the maldistribution rate calculated for each predetermined period is less than a preset threshold, and notifies the user that the maldistribution of the contact areas between the upper and lower jaw teeth is normal using the display 3, etc. On the other hand, in the example of Fig. 7(A2)-(D2), the detection device 1 determines that the maldistribution rate calculated for each predetermined period is equal to or greater than a preset threshold, and executes the abnormality processing described above.

[0078] In this way, the detection device 1 according to the modified example can notify the user of the result of detecting the bias in the contact area between the upper and lower jaw teeth. This allows the user to use the detection device 1 to check not only the early contact position but also the bias in the contact area between the upper and lower jaw teeth.

[0079] The detection device 1 may be a cloud-type server device. That is, the calculation device 11 (calculation unit) may have a function as a computer (processor, processing circuit) in the cloud-type server device. For example, the detection device 1 may be configured to be able to communicate with a user terminal such as a smartphone owned by a user or a subject. The detection device 1 may acquire three-dimensional data acquired by the three-dimensional scanner 2, and output output data including information on the early contact position detected based on the three-dimensional data to the user terminal. The user terminal may become able to communicate with the detection device 1 by starting an application downloaded in advance, and may acquire information on the early contact position based on the output data received from the detection device 1 and display it on a display. The detection device 1 itself may be a user terminal such as the above-mentioned smartphone.

[0080] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. Note that the configurations exemplified in the present embodiment and the configurations exemplified in the modified examples can be appropriately combined. [Explanation of symbols]

[0081] 1 detection device, 2 three-dimensional scanner, 3 display, 4 keyboard, 5 mouse, 10 detection system, 11 arithmetic unit, 12 memory, 13 storage device, 14 scanner interface, 15 display interface, 16 peripheral device interface, 17 media reading device, 18 communication device, 20 recording medium, 100 detection program.

Claims

1. A detection device for detecting an early contact position where early contact occurs when upper and lower teeth occlude, comprising: an input unit for inputting maxillary dentition data showing the three-dimensional shape of the maxillary dentition acquired by a three-dimensional scanner when the upper and lower dentitions are in an open-mouth state, mandibular dentition data showing the three-dimensional shape of the mandibular dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in the open-mouth state, and occlusion data showing the three-dimensional shape of the upper and lower dentitions acquired by the three-dimensional scanner when the upper and lower dentitions are in an occlusal state; a calculation unit that converts the maxillary dental row data, the mandibular dental row data, and the occlusion data into three-dimensional data in a common coordinate system, aligns each of the maxillary dental row data and the mandibular dental row data to corresponding portions of the occlusion data in the common coordinate system, thereby generating synthetic data indicating the three-dimensional shape of the upper and lower dental rows in the occlusion state, and detects the early contact position by updating one of the maxillary dental row data and the mandibular dental row data included in the synthetic data by moving it gradually away from the other dental row data so that the upper and lower dental rows are displaced from the occlusion state to the open state.

2. The detection device according to claim 1 , wherein the calculation unit detects, when updating one of the dental row data, a portion of the upper and lower dental rows where the upper and lower dental rows are in contact until the end as the early contact position.

3. The detection device according to claim 1 or claim 2, wherein the calculation unit updates the one of the dentition data based on at least one of jaw movement data estimated from the occlusion state, jaw movement data measured for the upper jaw and the lower jaw, and a predetermined average jaw movement data.

4. The detection device according to claim 3 , wherein the calculation unit corrects the at least one jaw movement data based on a check result of the occlusion of the upper and lower teeth using an articulation paper.

5. The detection device according to claim 1 or claim 2, wherein the calculation unit detects a bias in the contact area between the upper jaw dentition and the lower jaw dentition at predetermined intervals while updating the one of the dentition data.

6. A method for detecting a premature contact position by a computer, the method comprising: The detection method includes the steps of: acquiring maxillary dentition data indicating the three-dimensional shape of the maxillary dentition acquired by a three-dimensional scanner when the upper and lower dentitions are in an open-mouth state, mandibular dentition data indicating the three-dimensional shape of the mandibular dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in the open-mouth state, and occlusion data indicating the three-dimensional shape of the upper and lower dentitions acquired by the three-dimensional scanner when the upper and lower dentitions are in an occlusal state; a step of converting the maxillary dental row data, the mandibular dental row data, and the occlusion data into three-dimensional data in a common coordinate system, aligning each of the maxillary dental row data and the mandibular dental row data to corresponding portions of the occlusion data in the common coordinate system, thereby generating synthetic data indicating the three-dimensional shape of the upper and lower dental rows in the occlusion state, and detecting the early contact position by updating one of the maxillary dental row data and the mandibular dental row data included in the synthetic data by moving it gradually away from the other dental row data so that the upper and lower dental rows are displaced from the occlusion state to the open state.

7. A detection program for detecting an early contact position where early contact occurs when upper and lower teeth occlude, On the computer, maxillary dentition data showing a three-dimensional shape of the maxillary dentition acquired by a three-dimensional scanner when the upper and lower dentitions are in an open-mouth state; mandibular dentition data showing a three-dimensional shape of the mandibular dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in the open-mouth state; and acquiring occlusion data indicating a three-dimensional shape of the upper and lower dentitions acquired by the three-dimensional scanner when the upper and lower dentitions are in an occlusal state; a step of converting the maxillary dental row data, the mandibular dental row data, and the occlusion data into three-dimensional data in a common coordinate system, aligning each of the maxillary dental row data and the mandibular dental row data to corresponding portions of the occlusion data in the common coordinate system, thereby generating synthetic data indicating the three-dimensional shape of the upper and lower dental rows in the occlusion state, and detecting the early contact position by updating one of the maxillary dental row data and the mandibular dental row data included in the synthetic data by moving it gradually away from the other dental row data so that the upper and lower dental rows are displaced from the occlusion state to the open state.

8. A detection system for detecting an early contact position where early contact occurs when upper and lower teeth bite, comprising: a three-dimensional scanner for acquiring three-dimensional data representing the three-dimensional shapes of each of the upper and lower jaw dentitions; a detection device for detecting the early contact position based on the three-dimensional data acquired by the three-dimensional scanner; The detection device includes: an input unit for inputting maxillary dentition data indicating the three-dimensional shape of the maxillary dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in an open-mouth state, mandibular dentition data indicating the three-dimensional shape of the mandibular dentition acquired by the three-dimensional scanner when the upper and lower dentitions are in the open-mouth state, and occlusion data indicating the three-dimensional shape of the upper and lower dentitions acquired by the three-dimensional scanner when the upper and lower dentitions are in an occlusal state; a calculation unit that converts the maxillary dental row data, the mandibular dental row data, and the occlusion data into three-dimensional data in a common coordinate system, aligns each of the maxillary dental row data and the mandibular dental row data to a corresponding portion of the occlusion data in the common coordinate system, thereby generating synthetic data indicating the three-dimensional shape of the upper and lower dental rows in the occlusion state, and detects the early contact position by updating one of the maxillary dental row data and the mandibular dental row data included in the synthetic data by moving it gradually away from the other dental row data so that the upper and lower dental rows are displaced from the occlusion state to the open state.

Images