JPH0216132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for reproducing mandibular movement and a detection device used therefor. In particular, the present invention is characterized by detecting the position and movement of an arbitrary point using a detection device having six degrees of freedom, and creating a condyle block and an incisal block that can reproduce mandibular movement in an articulator based on the detection results. The aim is to make it possible to reproduce mandibular movement faithfully to the patient.

(Prior Art) In order to create a dental prosthesis or perform jaw-related diagnosis, it is necessary to measure and analyze the movement of the lower jaw, and various methods have been developed so far.

(Problems to be Solved by the Invention) Among these methods, the drawing method, strobe flash method, miniature lamp method, television method, etc. are relatively easy to use, but they are difficult to use when creating elaborate prostheses. Accuracy is low, and it is difficult to simultaneously record three-dimensional movements.Furthermore, it is difficult to fix the sensor to the upper jaw using magnetic detection methods or those that combine a photodiode and a light receiving element, and the device that is attached to the head can put tension on the muscles. Furthermore, in many cases, the head itself needs to be fixed so that it does not move because the floor surface or the like is used as a reference, which tends to cause pain to the patient. Additionally, a face bow is generally used to measure the three-dimensional movement of the mandible, but it requires time and effort to determine the reference point for measurement using the face bow and then measure the positional relationship between the reference point and the clutch. Moreover, since it uses soft tissues on the surface of the face, such as the temple, as a reference point, there are problems such as making accurate measurements difficult, making it difficult to measure and reproduce mandibular movement easily and with high precision. It was hot. Therefore, no method has yet been reported that provides a one-to-one correspondence between the function of positioning (three-dimensional position measurement) of a required part with respect to a device and the movement of that part. Moreover, this was the biggest problem when it came to practical use.

The present invention has been made in view of these problems, and aims to provide a method for reproducing mandibular movement that can be easily and accurately measured, and also to provide a detection device for use in this reproducing method. It is something that

(Means and operations for solving the problem) First, the device 1 for detecting mandibular movement of the present invention will be explained. This device 1 detects mandibular movement with 6 degrees of freedom by a combination of 6 rotary joints and a plurality of links. The horizontal axis Z in a three-dimensional coordinate system consisting of the vertical axis
three rotary joints 4, 5, 6 whose rotation axes are parallel to
Two rotary joints 7 and 8 whose rotational axes are parallel to the vertical axis
and one rotary joint 9 whose rotation axis is parallel to the front-rear axis Y.
and a plurality of links 15 interposed between these rotary joints 4, 5, 6, 7, 8, 9..., fixing member 2 and measurement probe 11 are fixed to the patient's upper jaw.
Alternatively, it is characterized in that the mandibular clutch 12 is connected to the movable member 3 to which it is attached so as to form six degrees of freedom. According to the present device 1, a two-dimensional plane S1 constituted by the vertical axis X and the front-back axis Y of the point to be measured
Detect the orthogonal projection and inclination angle from the angle changes of the three rotary joints 4, 5, and 6, and calculate the orthogonal projection onto the two-dimensional plane S2 composed of the longitudinal axis Y and the horizontal axis Z of the same point to be measured. and the inclination angle are detected by the angle changes of the two rotary joints 7 and 8, and a two-dimensional plane S is formed by the vertical axis X and the horizontal axis Z of the same point to be measured.
The inclination angle of the orthogonal projection with respect to 3 can be detected by the one rotary joint 9.

Further, the method for reproducing mandibular movement of the present invention utilizes the measured value by the above-mentioned detection device 1,
First, with the fixed member 2 of this device 1 fixed to the upper jaw, the measurement probe 11 is attached to the movable member 3, and the three-dimensional position data of three arbitrary points on the upper jaw, which serve as reference positions, are obtained from the rotary joints 4, 5, 6, Measure by changing the rotation angle of 7, 8, and 9. This is the first method of the present invention.
It is a characteristic of Next, the mandibular clutch 12 is attached to the movable member 3 and attached to the mandible, and the three-dimensional data of the position and posture of the point P to be measured accompanying the movement of the mandible is collected as described above from the rotary joints 4, 5, 6, 7,
Measurements are made over time based on changes in the rotation angle of 8 and 9. These measurement data are stored in the system controller 21, etc., which will be described later in the embodiment. Then, the three-dimensional position data measured from the upper jaw is replaced on the upper jaw model (prepared by taking impressions from the patient) attached to the articulator 23, and this is used as the reference position for reproduction. . Specifically, this replacement involves fixing the fixed member 2 of the detection device 1 to the maxillary model, and causing the measurement probe 11 attached to the movable member 3 to act on each point corresponding to the three measurement points. The position is set by comparing it with the stored position data. next,
Lower jaw model attached to the articulator 23 (same as above)
is moved based on the measured value of mandibular movement obtained from the patient, and the shape and position of the temporomandibular joint or cusp, etc., appropriate for the mandibular movement is calculated. Specifically, this calculation involves attaching the lower jaw clutch 12 to the movable member 3 of the detection device 1, attaching it to the lower jaw model, moving the lower jaw model in accordance with instructions from the system controller 21, and following this movement. The movement of the part corresponding to the temporomandibular joint or cusp of the moving articulator is detected by the change in the rotation angle of the rotary joints 4, 5, 6, 7, 8, 9 of the detection device 1, and this rotation information is input in advance. The appropriate shape and position of the temporomandibular joint or cusp are calculated by comparing the information with the known information of the articulator. Specifically, the condyle block 23b and the incisal block 23c of the articulator 23 are controlled by an automatic parallelometer 22, etc., which will be described later, according to the shape based on the above calculation result.
The processed condyle block 23b and incisal block 23c are installed at the calculated appropriate positions of the articulator 23. As a result of the patient-specific position and shape of the temporomandibular joint or cusp being correctly expressed in the condyle block 23b and the incisal block 23c, the lower jaw model can faithfully reproduce the movement of the patient's own mandible relative to the upper jaw model. This makes it possible to control the movement.

(Example) The present invention will be specifically described below with reference to an example shown in the drawings.

FIG. 1 is a side view of the detection device 1, in which 2 is a fixed member, 3 is a movable member, 4, 5, 6, 7, 8, 9 are rotary joints that also serve as angle sensors, and 10 is a fixed member 2.
The upper jaw clutch 11 and 12 are detachably attached to the attachment portion 2a of the movable member 3, and the measurement probe and the lower jaw clutch are detachable from the attachment portion 3a of the movable member 3. FIG. 2 shows the detection device 1 attached to the patient, with the maxillary clutch 10 attached to the fixed member 2 to fix the maxillary clutch 10 to the patient's upper jaw, and the movable member 3 equipped with various parts depending on the purpose. The measuring probe 11 is attached to the patient's lower jaw, or the mandibular clutch 12 is attached and fixed to the patient's lower jaw. 13 is a head belt for fixing;
14 is a hanger, which is used for the purpose of connecting the fixing member 2 and suspending the detection device 1;
The detection device 1 of the present invention only needs to be fixed to the upper jaw by the upper jaw clutch 10, and hanging is an auxiliary and not necessarily necessary. Note that this suspension may be performed using a long spring or the like suspended from a suitable support.

Now, the vertical axis (X axis) is based on the direction of the patient's face.
Considering a coordinate system in which the front-back axis (Y-axis) and the horizontal axis (Z-axis) are orthogonal to each other (the position of the origin is arbitrary), the plane composed of the X-axis and Y-axis is S1, and the plane composed of the Y-axis and Z-axis is The plane consisting of the X axis and the Z axis is S2.
3, the orientation of each rotary joint 4 to 9 with respect to each of these planes S1 to S3 is selected as follows. That is, the rotary joints 4, 5, 6 are arranged so that their axial directions are parallel to the Z-axis and the rotation angle within the plane S1 can be detected, and the rotary joints 7, 8, 9 are arranged so that their axial directions are parallel to the X-axis and are arranged in a plane. The rotary joint 9 is arranged so that the rotation angle within the plane S2 can be detected, and the rotary joint 9 is arranged so that the axial direction is parallel to the Y-axis and the rotation angle within the plane S3 can be detected. The rotary joint 4 is connected to the axis of the rotary joint 7 fixed to the end of the fixed member 2, and the link 15 is connected between the axis of the rotary joint 4 and the axis of the rotary joint 5 fixed to one end of the link 16. One end of the link 17 is connected to the shaft of the rotary joint 8 which is connected and fixed to the other end of the link 16.
A rotary joint 6 is attached to the axis of a rotary joint 9 fixed at the other end.
are connected, and the end of the movable member 3 is connected to the axis of the rotary joint 6.

With such a configuration, the movable member 3 can freely change its position and direction with respect to the fixed member 2 within the range determined by the links 15 to 17, and the position and direction at that time are different from each rotation. joint 4
It is detected by a rotation angle of ~9. In addition, each rotation joint 4 to 9 is obtained by six rotation joints.
It is only necessary to arrange it between the fixed member 2 and the movable member 3 so as not to interfere with the degree of freedom, and FIG. 2 shows one example of this, and other arrangements are not excluded.

FIG. 3 explains this relationship, where P indicates a specific location of the movable member 3, that is, a point to be measured, and an arrow indicates its direction (angle of inclination). Now, considering the orthogonal projection of the point P and the arrow onto each plane S1, S2, S3, since each link 15, 16, 17 has a constant length, the orthogonal projection P1 onto the plane S1 is 3.
If you know the rotation angles of rotation joints 4, 5, and 6,
It is uniquely determined from the length of each link 15, 16, 17 and each rotation angle, and the coordinates (x, y) of P1 with respect to the coordinate system are determined. Also, point P to plane S2
The orthogonal projection P2 can be obtained by finding z in the Z-axis direction of the coordinates (y, z), which can be obtained by
If you know the rotation angle of 8, link 15, 1 as above
It is uniquely determined by the relationship with the constant lengths of 6 and 17. Therefore, the coordinates (x,
y, z) are determined, and the three-dimensional position of point P is detected. Also, the angle of the orthogonal projection of the arrow onto the plane S1,
For example, the angle θ1 with respect to the Y axis is uniquely determined by the integrated value of the rotation angles of the three rotary joints 4, 5, and 6, and the angle of orthogonal projection of the arrow onto the plane S2, for example, the angle θ2 with respect to the Y axis is determined by two Rotating joints 7, 8
The angle of the orthogonal projection of the arrow onto the plane S3, for example, the angle θ3 with respect to the Z axis, is uniquely determined by the integrated value of the rotation angles of the rotary joint 9. Therefore, the three-dimensional direction of the arrow with respect to the coordinate system, that is, the attitude of the measured point P is detected.

The above relationship holds true for the measurement probe 11 attached to the movable member 3 and the mandibular clutch 12, so after initializing the fixed member 2 fixed to the upper jaw and appropriately determining the origin of the coordinate system, The measurement probe 11 can be used to measure the patient's dentition or the position of any arbitrary point on the face, or the mandibular clutch 12 can be measured over time to record mandibular movement.

In this way, in order to obtain the necessary measurement values using the six rotary joints 4 to 9, the rotary joints not only serve the role of mechanical joints, but also require the function of an angle sensor that can detect rotation angles. Although a small digital rotary encoder is used in this embodiment, it is also possible to use other types of angle sensors such as potentiometers. Note that the drawings do not show lead wires for each rotary joint.

In addition, in this embodiment, the three rotary joints 4,
5 and 6, and between them there is a link 15,
16 and 17 are arranged to increase the distance between each joint 4, 5, and 6, and two rotary joints 7 are used for lateral movement with relatively small weight, that is, movement parallel to plane S2. , 8, and further calculate the torsion of the lower jaw with the smallest weight, that is, plane S3.
For rotation in a plane parallel to It is done rationally. Therefore, when the lower jaw is moved, the resistance received from the detection device 1 is small, and the lower jaw can be moved naturally without any unnecessary load.

Now, using the detection device 1, as mentioned above, it is possible to measure the position of arbitrary points such as the patient's dentition, or to measure the mandibular movement.Next, based on this measurement result, the mandibular movement can be measured. We will explain how to reproduce this.

Figure 4 is a schematic diagram showing the base materials necessary for reproducing mandibular movement and their mutual relationships.
21 is a system controller that records measurement results, performs necessary calculations, controls the entire system, etc.;
Reference numeral 2 denotes an automatic parallelometer that processes the condyle block and incisal block of the articulator according to calculation results, and 23 an articulator to which a jaw model is attached to simulate mandibular movement. The system controller 21 has a built-in computer with a required capacity, and is appropriately equipped with an output device such as a display or a printer. The system controller 21 is programmed and inputted with the shape characteristic data of the articulator 23 in advance, and is compared with this input data when moving the mandibular model based on the measured value of the mandibular movement obtained above. The proper shape, position, etc. of the condile block 23b and the incisal block 23c are calculated to achieve smooth movement. Further, the automatic parallelometer 22 operates three times for each of the blocks 23b and 23c according to the calculation result of the system controller 21.
A device with the function of performing dimensional cutting is used. Further, the articulator 23 has a function of three-dimensionally adjusting the position of the tip 23a of the post corresponding to the condylar sphere of the mandible, and for example, a conventionally known Alcon type articulator or the like is used.

First, the fixed member 2 of the detection device 1 is fixed to the patient's upper jaw, the measurement probe 11 is attached to the movable member 3, and the positions of three points on the upper jaw, which serve as reference positions, are measured and recorded in the system controller 21. It is desirable to avoid soft tissues as much as possible and find these three points in locations that are easy to correspond to in the upper jaw model, for example, on specific teeth in the dental arch, in order to reduce errors. Next, the maxillary clutch 12 is attached to the movable member 3 and fixed to the mandible, and three-dimensional data of the position and posture of the mandible, which changes every moment as the mandible moves, is measured at predetermined sampling intervals and recorded in the same manner as above. . This completes the operation in the medical room.

Next, the upper jaw model obtained in advance is placed in the articulator 23.
The position of the three points on the upper jaw model corresponding to the three points previously determined on the patient's upper jaw is similarly measured using the detection device 1, and the reference position for reproduction in the articulator 23 is thereby set. do. Once the reference position is determined, the mandibular movement can be reproduced in the articulator 23 by attaching the mandibular model to a predetermined position relative to this reference position and moving the mandibular model according to the recorded mandibular movement data. , by substituting mandibular movement data into pre-programmed arithmetic expressions, the position and shape of the mandibular joint, which is the basis of mandibular movement, i.e., the condylar bulb and the corresponding glenoid fossa, are determined.
The system controller 21 calculates the position of each cusp of the upper and lower tooth rows.

Based on this calculation result, the position of the post tip 23a of the articulator 23 is adjusted, and the condyle block 23b and incisal block 2 of the articulator 23 are adjusted.
Parallelometer 2 automatically processes 3c
2, and finally set it on the articulator 23. In this way, the relative movement between the upper jaw model and the lower jaw model attached to the articulator 23 can faithfully reproduce the movement of the patient's lower jaw relative to the upper jaw.

The post of the articulator is attached to the mandibular model support plate so that its position can be adjusted in two dimensions in the area as shown by the arrow in Figure 4, and its height can be adjusted using a screw shaft, etc. , which is similar to that provided in the known Alcon type articulator. Also,
Although the above explanation describes the case where the upper jaw model is attached to the articulator 23 first, the same result can be obtained even if the lower jaw model is attached first.

In general, the manufacturing process of a prosthesis consists of: 1. Adjustment of the articulator;
It can be roughly divided into four steps: 2. Design, 3. Completion of the wax mold and replacement with metal or synthetic resin, and 4. Polishing, but these steps are mostly done manually and require countless tools. , and requires complex operations. However, by performing the above calculation processing on the detection results obtained by this device, steps 1 to 3 of the above manufacturing processes can be automated. Note that these calculation processes are performed using CAD (Computer Aided Design).
The operation can be simplified by using the design method.

(Effects of the Invention) As described above, the method for reproducing mandibular movement of the present invention can accurately set the positions of joints that cannot be directly touched and reproduce the movement of the mandible with high precision. It is effective in realizing more complete dental care such as occlusal diagnosis and prosthesis manufacturing.

In addition, the mandibular movement detection device of the present invention connects a fixed member and a movable member by six rotary joints that also function as angle sensors and are arranged rationally according to the movement of the mandible. The position of the lower jaw and the movement of the mandible can be measured three-dimensionally with high precision, and it is easy to operate without the need for the labor required when measuring with a face bow, and it is also easy to reduce the size and weight. In addition, since there is no need to fix the head, there is no burden on the patient, and mandibular movement can be recorded in a natural state.

[Brief explanation of drawings]

Fig. 1 is a side view of an embodiment of the detection device of the present invention, Fig. 2 is a perspective view of the same in use, Fig. 3 is a diagram explaining the principle of operation, and Fig. 4 is an implementation of the reproduction method of the present invention. FIG. (Explanation of symbols) 1...detection device, 2...fixed member, 3...movable member, 4, 5, 6, 7, 8, 9...rotary joint, 10...maxillary clutch, 11...measuring probe, 12...mandibular clutch, 21... System controller, 22... Automatic parallelometer, 23... Articulator, 23b... Condyle block, 23c... Incisal block.

Claims (1)

[Scope of Claims] 1. Three rotary joints 4, 5 whose rotational axes are parallel to the horizontal axis Z in a three-dimensional coordinate system consisting of the vertical axis , 6, two rotary joints 7 and 8 whose rotational axes are parallel to the vertical axis , 8, 9, the fixed member 2 fixed to the upper jaw of the patient and the movable member 3 to which the measurement probe 11 or the mandibular clutch 12 is attached are connected to form six degrees of freedom. The device 1 for detecting mandibular movement is constructed by attaching the measurement probe 11 to the movable member 3 with the fixed member 2 fixed to the upper jaw, and measuring the three-dimensional position data of arbitrary three points on the upper jaw as reference positions. Measurements are made by changes in the rotation angles of the rotary joints 4, 5, 6, 7, 8, and 9. Next, the mandibular clutch 12 is attached to the movable member 3 and attached to the mandible, and the measured point P is measured as the mandible moves. The position and inclination angle of the orthogonal projection on the two-dimensional plane S1 constituted by the vertical axis The position and inclination angle of the orthogonal projection on the two-dimensional plane S2 composed of the axis Y and the horizontal axis Z are detected by the angle changes of the two rotary joints 7 and 8, and the vertical axis The inclination angle of the orthogonal projection to the two-dimensional plane S3 constituted by the horizontal axis Z is detected by the one rotary joint 9, and the three-dimensional position data of the three points measured from the upper jaw is collected by the articulator 23 attached to the articulator 23. The lower jaw model attached to the articulator 23 is moved based on the measured value of the mandibular movement obtained above, and the temporomandibular joint or cusp, etc., which is appropriate for the mandibular movement, is replaced with the upper jaw model and used as a reference position during reproduction. The shape and position of the articulator 23 are adjusted according to the shape based on the above calculation results.
A method for reproducing mandibular movement, characterized in that the condyle block 23b and incisal block 23c are processed and the condyle block 23b and incisal block 23c are installed at calculated appropriate positions. 2 Three rotary joints 4, 5, 6 whose rotational axes are parallel to the horizontal axis Z in three-dimensional coordinates consisting of the vertical axis Two rotary joints 7 and 8 whose rotational axes are parallel to The fixed member 2 fixed to the upper jaw of the patient and the movable member 3 to which the measurement probe 11 or the mandibular clutch 12 is attached are connected with six degrees of freedom by a plurality of interposed links 15. The position and inclination angle of the orthogonal projection of the measured point on the two-dimensional plane S1 constituted by the vertical axis
6, and the position and inclination angle of the orthogonal projection of the measured point to the two-dimensional plane S2 composed of the longitudinal axis Y and the horizontal axis Z are determined by the angular changes of the two rotary joints 7 and 8. and the inclination angle of the orthogonal projection of the point to be measured onto a two-dimensional plane S3 constituted by the vertical axis X and the horizontal axis Z can be detected by the one rotary joint 9. Movement detection device.