KR100972456B1 - Method and apparatus for estimating TMJ movement - Google Patents

Abstract

The present invention relates to a method for tracking and reproducing movement of the temporomandibular joint and an apparatus for performing the same.
In the present invention, in order to form a three-dimensional upper and lower jaw model using the subject's three-dimensional image data, the subject is equipped with a display device with a marker capable of recording in the three-dimensional image data at the time of imaging. At this time, in order to fix the display device, a sprint in which the dental occlusal state of the subject is recorded is used in combination with the display device. Whenever the subject is changed, the sprint may be replaced with a recording of the dental occlusal state of the subject.

Description

Method for tracking and reproducing temporomandibular joint movement and apparatus for performing the same {Method and apparatus for estimating TMJ movement}

The present invention relates to a method for tracking and reproducing temporomandibular joint movement and an apparatus for performing the same.

Recently, the incidence of temporal mandibular joint (TMJ) disease is increasing due to the increase of stress as society is advanced and specialized. These TMJ diseases need to be diagnosed and treated correctly before they develop into malignant jaw joint disease. TMJ is the central axis of mandibular movement and plays an essential role in chewing and pronunciation through rotational and sliding movements.

On the other hand, it is very important to obtain predictive data on the functional change and treatment effect of temporomandibular anatomy after surgical treatment of upper jaw and lower jaw. However, the mandibular movement is not only very complicated but also difficult to measure. In general, articulators using gypsum models used in clinical practice use simplified models that rotate about one axis to measure the movement of the mandible. However, in the opening and closing of the jaw, the TMJ performs a combination of a rotational motion and a sliding motion, not a simple rotational motion about the hinge axis between the condyles.

Therefore, the simple representation in which the mandible simply rotates around the mandibular condyle may realize a wrong jaw movement because the rotating axis may not be associated with the actual mandibular movement path. Therefore, in order to accurately reproduce the motion in the TMJ, it is necessary to analyze the motion of the TMJ in three dimensions.

Current clinical practice measures mandibular movement with six degrees of freedom using an optical system that includes a CCD camera to analyze mandibular movement. In such a system, the position of the optical marker attached to the upper and lower teeth is continuously measured to obtain information such as position, velocity, and acceleration related to mandibular motion. However, this measurement method has a disadvantage in that it does not provide information related to the anatomical structure of the patient. In addition, even if accurate mandibular motion information is measured, inaccurate TMJ motion may be reproduced due to geometric differences in the shape of mandibular joints between patients when using standard TMJ models to reproduce mandibular movement.

Therefore, in order to overcome this problem, a system for analyzing motion in TMJ using a patient's own three-dimensional model is required.

The present invention is to provide a method for tracking and reproducing temporomandibular joint movement, which can accurately measure and reproduce the movement of the temporomandibular joint, and a motion information acquisition device therefor.

Method for tracking and reproducing the temporomandibular joint movement of the subject according to the characteristics of the present invention,

Recording the dental occlusal state of the subject in a first device; Combining a second device including a plurality of markers recorded in the 3D image data with the first device when capturing 3D image data to form a third device; Acquiring the 3D image data from the subject equipped with the third apparatus through the photographing; And mapping the 3D image space corresponding to the 3D image data to the physical space based on the position data of the plurality of markers recorded in the 3D image data and the position data of the physical spaces of the plurality of markers. Steps.

According to the present invention, when photographing to form a 3D upper and lower jaw model, the display unit including a marker appearing in the 3D image data every time the subject is changed is used as it is, and only the sprint in which the subject's orthodontic state is recorded is replaced. It can be used, which has the effect of lowering the unit cost of the image mapping display device.

In addition, when acquiring upper and lower jaw movement data using an optical position tracking camera, the relative movement of the position data acquired through the device mounted on the subject's dentition based on the position data acquired through the device mounted on the forehead of the subject Since the mandible movement is measured incorrectly due to the movement of the maxillary, there is an effect of preventing the calculation of wrong upper and lower jaw movement data.

1 is a schematic diagram illustrating a motion tracking and reproduction system according to an exemplary embodiment of the present invention.
2 illustrates an image mapping display device according to an exemplary embodiment of the present invention.
3 illustrates an example of a display unit according to an exemplary embodiment of the present invention.
4 illustrates an example of a sprint according to an embodiment of the present invention.
Figure 5 illustrates an example of a sprint before the occlusal surface popular silicon is attached to the occlusal surface impression tray according to an embodiment of the present invention.
6 illustrates an example of a motion display device according to an exemplary embodiment of the present invention.
7 illustrates an example of a fixing device according to an embodiment of the present invention.
8 illustrates an example of a first optical marker according to an embodiment of the present invention.
9 illustrates an example of a motion device according to an exemplary embodiment of the present invention.
10 illustrates an example of a second optical marker according to an embodiment of the present invention.
11 is a flowchart illustrating a method for tracking and reproducing motion of a TMJ according to an embodiment of the present invention.
12 is a flowchart illustrating a method of obtaining CT data according to an embodiment of the present invention.
13 is a flowchart illustrating a method of reproducing upper and lower jaw movements according to an embodiment of the present invention.
14 illustrates an example of a upper and lower mandible surface model formed by region division in a three-dimensional CT image according to an exemplary embodiment of the present invention.
15 illustrates an example of reproducing the movement of the maxilla and the mandible using a three-dimensional upper and lower jaw model according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. Also, the term "part" or the like, as described in the specification, means a unit for processing at least one function or operation, and may be implemented by hardware, software, or a combination of hardware and software.

Hereinafter, the motion tracking and reproducing system and method of the temporomandibular joint according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

On the other hand, below, the object to track the motion of the TMJ is named and used "object".

Next, a motion tracking and reproducing system for forming a 3D upper and lower jaw model according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 7.

1 is a schematic diagram illustrating a motion tracking and reproduction system according to an exemplary embodiment of the present invention.

Meanwhile, an embodiment of the present invention will be described using a computed tomography (CT) data to form a 3D upper and lower jaw model as an example. However, this is not a limitation of the present invention. In the present invention, it is also possible to form a three-dimensional upper and lower jaw model using other forms of three-dimensional image data.

Referring to FIG. 1, the motion tracking and reproduction system includes a display device 100 for image mapping, a 3D model generating device 200, a motion display device 300, a motion data acquisition device 400, and a reproduction device 500. Include.

When performing CT imaging to acquire CT data, the image mapping display device 100 is mounted on the teeth of the subject.

The 3D model generating apparatus 200 obtains CT data through CT imaging of a subject equipped with the image mapping display device 100, and forms a 3D upper and lower jaw model using the data.

The motion display device 300 includes a plurality of reflectors and is mounted on the forehead and the teeth of the subject, and serves as a means for optically displaying the upper and lower jaw movements of the subject over time.

The motion data obtaining apparatus 400 continuously records the movements of the reflectors on the movement display apparatus 300 mounted on the subject, and acquires the movement data of the upper jaw and the upper jaw from the movements of the recorded reflectors.

The reproducing apparatus 500 reconstructs the subject's upper and lower jaw movements by correlating the subject's upper and lower jaw movement data with the subject's three-dimensional upper and lower jaw models.

2 illustrates an example of an image mapping display device 100 according to an exemplary embodiment.

Referring to FIG. 2, the display apparatus 100 for image mapping includes a display unit 110 and a sprint 120, and the sprint 120 may be attached to and detached from the display unit 110.

In the exemplary embodiment of the present invention, the case in which the sprint 120 is coupled with the display unit 110 through the connection unit 130 in the form of a block will be described as an example. However, this coupling method does not limit the present invention. It is possible to couple the sprint 120 to the display unit 110 in various ways such as in combination.

3 illustrates an example of the display unit 110 according to an exemplary embodiment of the present invention, in which six markers for mapping 111 in the form of a metal ball are arranged at a predetermined interval on a support.

Referring to FIG. 3, the display unit 110 includes a plurality of markers 111 for mapping, which are materials that can be recorded on CT data such as metal spheres. The position data of the mapping marker 111 is recorded in the CT data during CT imaging, and provides mapping reference data for mapping the CT data of the subject into the physical space.

Meanwhile, in the exemplary embodiment of the present invention, the case in which six mapping markers 111 are mounted on the display unit 110 will be described as an example. However, the present invention describes the number of mapping markers 111 mounted on the display unit 110. It is possible to change. In addition, in the embodiment of the present invention, the mapping marker 111 is inserted and mounted in a row on the support of the display unit 110, but in the present invention, it is also possible to change the mounting method of the mapping marker 111.

4 illustrates an example of a sprint 120 according to an embodiment of the present invention, and FIG. 5 illustrates a sprint before the occlusal surface popular silicon 122 is attached to the occlusal surface impression tray 121. An example of 120 is shown.

Referring to FIG. 4, the sprint 120 includes an occlusal surface pulling tray 121 and an occlusal surface popular silicon 122, and serves to fix the display device 100 for image mapping to the teeth of a subject. .

The occlusal surface impression tray 121 includes a first structure 1211 coupled to the display unit 110 and a second structure 1212 into which the occlusal surface popular silicon 122 is inserted.

A semicircular hole is formed in the upper surface of the second structure 1212 as shown in FIG. 5, and the occlusal surface popular silicon 122 is inserted into the semicircular hole as shown in FIG. 4.

The occlusal surface popular silicon 122 is inserted into the second structure 1212 of the occlusal surface raising tray 121, and the dental occlusal state of the subject is recorded. As described above, the occlusal surface popular silicon 122 in which the orthodontic occlusal state of the subject is recorded allows the image mapping display device 100 to be precisely coupled to the subject's dental dentition.

On the other hand, as described above, the sprint 120 needs to be newly produced whenever the subject changes. Therefore, when the subject is changed as in the embodiment of the present invention, the display unit 110 is used as it is and the sprint 120 is replaced and used. The apparatus 100 for mapping the image 100 every time the subject is changed is used. Compared to the new production method, the cost is reduced.

6 illustrates an example of a motion display apparatus 300 according to an exemplary embodiment.

Referring to FIG. 6, the motion display device 300 includes a fixing device 310 and a moving device 320, and the fixing device 310 and the moving device 320 are coated with a material sensitive to infrared rays. And a plurality of reflectors recordable by the optical positioning camera.

The fixing unit 310 and the movement unit 320 are mounted on the forehead and the teeth of the subject, respectively, and the reflectors attached to the fixing unit 310 and the movement unit 320 move to obtain upper and lower movement data. The data acquisition apparatus 400 is a recording target for continuously recording movement.

The motion data obtaining apparatus 400 continuously records the movements of the reflectors attached to the fixing unit 310 and the movement unit 320 by using an optical position tracking camera, and extracts the continuous position data of the reflectors. do. The upper and lower motion data is calculated by detecting a change in the position data of the reflectors attached to the movement device 320 based on the position data of the reflectors attached to the fixing device 310. Here, the upper and lower jaw motion data includes translation information in a 3D vector format and rotation information in a 3X3 matrix format.

7 illustrates an example of a fixing device 310 according to an embodiment of the present invention, and FIG. 8 illustrates an example of the first optical marker 311 according to an embodiment of the present invention.

Referring to FIG. 7, the fixing device 310 includes a first optical marker 311 and a head fixing device 312.

As illustrated in FIG. 8, the first optical marker 311 is coated with a material sensitive to infrared rays so that a plurality of reflectors 3111 that can be recorded by the optical positioning camera are attached to the end of the x-shaped support. Such movements of the reflectors 3111 are continuously recorded by the motion data acquisition apparatus 400, and the motion data acquisition apparatus 400 moves the first position data extracted from the movements of the continuously recorded reflectors 3111. Used for calculation.

The head fixing device 312 is a modified form of the headset, and serves to fix the fixing device 310 to the forehead of the subject.

9 illustrates an example of the movement device 320 according to an embodiment of the present invention, and FIG. 10 illustrates an example of the second optical marker 321 according to an embodiment of the present invention.

Referring to FIG. 9, the movement device unit 320 includes an image mapping display device 100 and a second optical marker 321.

As shown in FIG. 10, the second optical marker 321 is implemented by attaching a reflector 3211 that can be recorded by an optical positioning camera at the end of the x-shaped support. The movement of the reflector 3211 is continuously recorded by the motion data obtaining apparatus 400, and the motion data obtaining apparatus 400 calculates the motion data by extracting second position data extracted from the movement of the continuously reflecting object 3211. Use when

The image mapping display device 100 serves to fix the movement unit 320 to the teeth of the subject.

Meanwhile, in the exemplary embodiment of the present invention, since the relative change of the second position data corresponding to the mandibular movement is obtained based on the first position data corresponding to the mandibular movement, the upper and lower jaw movement data is obtained. Therefore, the mandible movement is prevented from being measured incorrectly, thereby producing an incorrect upper and lower mandible movement data.

Next, a method of tracking the movement of the upper and lower jaw by the motion tracking system according to an exemplary embodiment of the present invention will be described in detail with reference to the drawings.

11 is a flowchart illustrating a method for tracking and reproducing motion of a TMJ according to an embodiment of the present invention.

Referring to FIG. 11, the motion tracking and reproducing system acquires CT data by CT imaging a subject equipped with the image mapping display device 100 (S101).

The 3D CT image space corresponding to the obtained CT data is mapped to the actual physical space (S102). This is a process of synchronizing the upper and lower jaw relationship of the subject and the initial positional relationship when measuring the motion data during CT imaging.

To this end, the motion tracking and reproducing system measures a three-dimensional spatial position in the physical space of the mapping marker 111 attached to the image mapping display device 100 using a measuring device (not shown). That is, the coordinates of the reflectors attached to the measuring device (not shown) are measured using an optical position tracking camera, and the marker for mapping located at the end of the support of the display apparatus 100 for image mapping by applying an offset value based on the measured coordinates. The three-dimensional spatial position of the field 111 is measured. Here, a method of measuring the three-dimensional spatial position in the physical space of the mapping marker 111 by using the reflectors attached to the measuring device is a well-known technique, and a detailed description thereof will be omitted. .

On the other hand, when the position in the physical space of the mapping markers 111 is measured, the position in the physical space of each mapping marker 111 corresponds to the position in the three-dimensional CT data one-to-one, and the following equation Determine the Affine transformation as shown in 1.

Here, x, y, z means the position in the physical space of the mapping marker 111, x ', y', z 'means the position in the three-dimensional CT data. In addition, α ₃ in α ₁ is a value related to parallel movement in three axes, and α ₁₂ in α ₄ is a value related to rotation movement about three axes . Meanwhile, in Equation 1, only four corresponding points are determined in three dimensions to determine 12 parameters, but since six corresponding points are available, 12 parameters are determined by the least squares method.

After mapping the 3D CT image space to the physical space , the motion tracking and reproducing system uses an optical positioning camera to position data (first position) of the reflectors 3111 and 3211 of the movement display apparatus 300 mounted on the subject. Data and second position data) are measured continuously. Here, the first position data and the second position data are synchronized with each other, and the motion tracking and reproducing system records time information together when recording the position data.

Then, the motion tracking and reproducing system acquires motion data by grasping the motion of the upper and lower jaws by time using the position data (first coordinate data and second position data) recorded together with the time information (S103). Here, the upper and lower jaw movement data includes parallel movement information in a 3D vector format and rotation movement information in a 3X3 matrix form, which are continuously measured, and the parallel movement information is a negative value of the first position data corresponding to the position of the maxilla. In addition to the second position data corresponding to the position of the calculation, the rotation movement information may be calculated by multiplying the inverse matrix of the first position data by the second position data.

The motion tracking and reproducing system acquiring the maxillary movement data generates a three-dimensional upper and lower jaw model in which the maxilla and the mandala are separated from each other using CT data (S104), and the maxillary movement data is transferred to the three-dimensional maxillary mandibular model. Correspondingly, the motion of the upper and lower jaw, that is, the motion of the TMJ, is reproduced (S105). Here, the reproduction of the maxillary and mandibular movements in the three-dimensional upper and lower jaw models consists of the relative movements of the mandibles with the maxilla fixed.

12 is a flowchart illustrating a method of obtaining CT data according to an embodiment of the present invention.

Referring to FIG. 12, before the CT scan of the subject, the occlusal surface popular silicon 122 is first inserted into the sprint 120, and the dental occlusal state of the subject is recorded (S201). In operation S202, the sprint 120 in which the dental occlusal state of the subject is recorded is combined with the display unit 110.

In addition, the image mapping display device 100 in which the display unit 110 and the sprint 120 are combined is mounted on the teeth of the subject (S203), and the CT of the target image mounted with the image mapping display device 100 is CT. Acquire data (S204). Here, the CT data includes the position data of the mapping marker 111 attached to the display unit 110.

Meanwhile, in the exemplary embodiment of the present invention, the case in which the dental occlusal state of the subject is recorded on the sprint 120 before being combined with the display unit 110 has been described. However, in the present invention, after the display unit 110 and the sprint 120 are combined, It is also possible to record the dental occlusal state of the subject on the occlusal surface popular silicon 122 of the sprint 120.

13 is a flowchart illustrating a method of reproducing upper and lower jaw movements according to an embodiment of the present invention. In addition, FIG. 14 illustrates an example of the upper and lower jaw surface models formed by region division in a three-dimensional CT image according to an embodiment of the present invention. An example of reproducing the movement is shown.

Referring to FIG. 13, in order to reproduce the motion of the upper and lower jaw, the motion tracking and reproducing system first of all uses a three-dimensional surface rendering model and a mandibular surface model as shown in FIG. To form (S301).

Then, the initial position of the maxilla and mandible in the three-dimensional upper and lower jaw model is set (S302). Here, the initial positions of the maxilla and the mandible are set to the same positional relationship as in CT imaging. This is because the maxillary and maxillary motion data records the maxillary and mandibular movements started at the same position as the CT scan, and thus the initial positional relationship of the 3D maxillary and maxillary motion data is synchronized when the motion is reproduced.

When the initial position is synchronized, the motion tracking and reproducing system corresponds to the upper and lower jaw models in three dimensions to reproduce the upper and lower jaw movements (S303). Here, the motion tracking and reproducing system reproduces the movement with the mandibular movement while the maxilla is fixed in the 3D upper and lower jaw model as shown in FIG. 15, and the position of the mandible ( T _{man _ image} ) in the 3D upper and lower jaw model is It is calculated through the following equation (2).

Here, T _{ref _ init} and T _{man _ init} are the initial positions of the maxilla and mandible in the physical space. In addition, T _ref and T _{man _ physical} are positions according to the movement of the maxilla and the mandible in the physical space. And, M _req is a transformation equation for mapping the position of the mandible in the physical space to the position of the mandible in the 3D upper and lower jaw model, and the embodiment of the present invention uses the above-described Affine transformation equation (1).

In Equation 2, the position according to the movement of the mandible in the three-dimensional upper and lower jaw models is determined by the position ( T _{man _ physical} ) according to the movement of the mandible in the physical space to determine the relative position in the physical space. The inverse transform of the maxillary position ( T _ref ^-1 ) is multiplied and the inverse transform of the mandibular initial position ( T _{ref _ init} ^-1 T _{man _ init} ) is multiplied to synchronize with the initial position. Finally, the position of the mandible T _{man _ image} in the image space corresponding to the 3D upper and lower mandible model is calculated by applying the Affine transform M _reg .

The motion tracking and reproducing system continuously calculates the position of the mandible and applies it to a three-dimensional upper and lower mandible model, thereby reproducing the mandibular motion.

Meanwhile, the motion tracking and reproducing system may set a measurement point at any position of the mandible to analyze the movement of a specific position of the mandible when reproducing the mandible movement. In other words, while observing the shape of the mandible in the sagittal plane, the coronal plane, and the axial direction in the CT data, a three-dimensional measurement point may be set at the location of interest. When the measuring point is set, the motion tracking and reproducing system can continuously calculate the position of the measuring point according to the movement of the mandible using the same method as the above-described method of calculating the mandible position. This is because all points located in the mandible have the same movement as the mandible because they are the same rigid body belonging to the mandible.

On the other hand, the measuring point may be located both on the surface or the inside of the mandible. Therefore, it is possible to track the movement of the measuring points on the surface of the condylar prosess or the surface of the coronoid process that cannot be measured non-invasively from outside the human body. The location information of the continuously tracked measurement points provides a specific movement trajectory for each subject, and the movement trajectory is analyzed through a PCA analysis method to diagnose the subject's TMJ movement abnormality.

The embodiments of the present invention described above are not only implemented by the apparatus and method but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded, The embodiments can be easily implemented by those skilled in the art from the description of the embodiments described above.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

100 Display for image mapping, 110 display, 111 mapping marker, 120 sprint, 121 occlusal impression tray, 122 occlusal popular silicon, 130 connector, 200 3-D model generator, 300 motion display, 310 fixture Unit, 311 first optical marker, 312 head fixing unit, 320 movement unit, 400 movement data acquisition unit

Claims (11)

In the method of tracking and reproducing the movement of the temporomandibular joint of the subject,
Recording the dental occlusal state of the subject in a first device;
Combining a second device including a plurality of markers recorded in the 3D image data with the first device when capturing 3D image data to form a third device;
Acquiring the 3D image data from the subject equipped with the third apparatus through the photographing; And
Mapping a three-dimensional image space corresponding to the three-dimensional image data to the physical space based on the position data of the plurality of markers recorded in the three-dimensional image data and the position data in the physical space of the plurality of markers.
Movement tracking and reproduction method comprising a. The method of claim 1,
If the subject is changed, recording the changed occlusion state of the subject in a fourth device; And
Removing the first device from the second device and coupling the fourth device to the second device to form a new third device
Motion tracking and reproducing method further comprising. The method of claim 1,
Setting initial positions of the maxilla and mandible of the subject;
Continuously recording movements of the fourth device and the fifth device, each of which is mounted on the subject's forehead and teeth and has a plurality of reflectors coated with infrared material;
Acquiring first position data and second position data from the movements of the recorded fourth and fifth devices; And
Acquiring upper and lower jaw movement data based on the first position data and the second position data;
Movement tracking and reproduction method comprising a. The method of claim 3, wherein
The initial position of the maxilla and mandible of the subject is set to the movement tracking and reproduction method of the same positional relationship as when computed tomography. The method of claim 3, wherein
The upper and lower jaw motion data is a motion tracking and reproduction method comprising a parallel movement information and rotation movement information. 6. The method of claim 5,
And the parallel movement information is calculated by adding a negative value of the first position data to the second position data. 6. The method of claim 5,
And the rotation movement information is calculated by multiplying an inverse of the first position data by the second position data. 6. The method of claim 5,
Generating a three-dimensional upper and lower jaw model in which the upper and lower jaw are separated from each other by using the three-dimensional image data;
Motion tracking and reproducing method further comprising. The method of claim 8,
Reproducing the movement of the temporomandibular joint by matching the motion data to the three-dimensional upper and lower jaw models
Motion tracking and reproducing method further comprising. The method according to claim 8 or 9,
The location of the mandible in the three-dimensional upper and lower jaw model is the following equation
T _{man _ image} = M _req ( T _{ref _ init} ^-1 T _{man _ init} ) ^-1 T _ref ^-1 T _{man _ physical}
Where T _{ref _ init} and T _{man _ init} are the initial positions of the maxilla and mandible in the physical space, T _ref and T _{man _ physical} are the positions of the maxilla and mandible movements in the physical space, and M _req is the physical space This is a transformation formula to map the position of the mandible in the mandible to the position of the mandible in the 3D upper and lower mandible model.
Motion tracking and reproducing method, characterized by satisfying the. The method according to any one of claims 1 to 9,
The 3D image data is computed tomography data movement tracking and reproduction method.

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