阅读说明：本技术 一种髁突运动轨迹确定方法 (Condyle motion trajectory determination method ) 是由 曹清华 许振丰 徐玉峰 云峰 于 2020-11-18 设计创作，主要内容包括：本发明涉及一种髁突运动轨迹确定方法,包括：建立坐标系：建立用于轨迹测量发射坐标系和接收坐标系；静态测量：在发射坐标系下,测量左、右侧髁突以及随动点的静态位置,计算左、右侧髁突与随动点的位置差；进行坐标转换,得到接收坐标系下左、右侧髁突与随动点的位置差；动态测量：测量跟随下颌运动的随动点的系列位姿数据；根据所述位姿数据,以及接收坐标系下左、右侧髁突与随动点的位置差,计算左、右侧髁突的动态轨迹。本发明的方法可确定髁突的运动轨迹,而且不依赖于假设条件下的等边三角形及三角形与咬合面的夹角,具有个体性、实用性的优点。(The invention relates to a method for determining a motion track of an condylar process, which comprises the following steps: establishing a coordinate system: establishing a transmitting coordinate system and a receiving coordinate system for track measurement; static measurement: measuring the static positions of the left and right condyles and the following point under the emission coordinate system, and calculating the position difference between the left and right condyles and the following point; performing coordinate conversion to obtain the position difference between the left and right condyles and the follow-up point under the receiving coordinate system; dynamic measurement: measuring a series of pose data of a follow-up point which follows the movement of the lower jaw; and calculating the dynamic tracks of the left and right condyles according to the pose data and the position difference between the left and right condyles and the follow-up point under the receiving coordinate system. The method can determine the motion trail of the condylar process, does not depend on an equilateral triangle and an included angle between the triangle and the occlusal surface under the assumed condition, and has the advantages of individuality and practicability.)

1. A condylar motion trajectory determination method is characterized by comprising the following steps:

establishing a coordinate system: establishing two sets of coordinate systems for track measurement, wherein the two sets of coordinate systems comprise a transmitting coordinate system which takes the transmitter as an origin and takes the front, the upper and the right of the transmitter as three-axis directions; a receiving coordinate system which takes a follow-up point moving along with the lower jaw as an origin and takes the front, the upper and the right of a receiver fixed at the follow-up point as three axial directions; the follow-up point keeps the positions of the right and left condyles unchanged during follow-up;

static measurement: measuring the static positions of the left and right condyles and the following point under the emission coordinate system, and calculating the position difference between the left and right condyles and the following point; performing coordinate conversion to obtain the position difference between the left and right condyles and the follow-up point under the receiving coordinate system;

dynamic measurement: measuring a series of pose data of a follow-up point which follows the movement of the lower jaw; and calculating the dynamic tracks of the left and right condyles according to the pose data and the position difference between the left and right condyles and the follow-up point under the receiving coordinate system.

2. The method for determining the motion trajectory of the condyles of claim 1, wherein the static positions of the left and right condyles are obtained by averaging after a plurality of measurements when the static positions of the left and right condyles are measured.

3. The condylar motion trajectory determination method of claim 2,

when the static position measurement of the left and right condyles is carried out, the human head keeps still and the teeth are kept closed; and (3) contacting the measurement reference point of the receiver to the position of the human face condyle, and performing multiple measurements by taking the measurement reference point of the receiver as a fulcrum.

4. The condylar motion trajectory determination method of claim 1, wherein the determination of the follow-up point comprises: wearing a face bow on a head of a person, installing an occlusion fork at the same time, keeping the head of the person still, adjusting the occlusion fork at a proper position, keeping teeth closed, and connecting a measurement datum point of a receiver to the other end of the occlusion fork; the point of attachment of the receiver to the bite fork is taken as the following point.

5. The condylar motion trajectory determination method of claim 4,

one end of the occlusion fork is stuck on the lower dentition and fixedly connected with the middle incisor, and the occlusion fork and the condyles on the two sides form a rigid structure.

6. The method for determining the motion trail of the condyles according to claim 1, wherein the calculation process of the position difference between the left and right condyles and the follow-up point under the receiving coordinate system comprises;

calculating the position difference between the right condyle and the follow-up point under the emission coordinate systemDifference in position between the left condyle and the following point

Performing coordinate conversion to obtain a position difference under a receiving coordinate system;

wherein: j is 1 as the right condyle, and j is 2 as the left condyle; and L is a coordinate transformation matrix from a transmitting system to a receiving system.

7. The condylar motion trajectory determination method of claim 6,

coordinate transformation matrix from transmitting system to receiving system

Wherein the content of the first and second substances,

TC0, TP0, TR0 are heading attitude angle, pitch attitude angle, roll attitude angle of the receiver at the static position of the follower point, respectively.

8. The condylar motion trajectory determination method of claim 1, wherein in the dynamic measurement, the mandible moves forward, backward, left and right to drive the receiver fixed at the follow-up point to follow up, receive the emission signal of the emitter, and obtain pose data of a series of receivers by measurement: p4(TX 4)_k、TY4_k、TZ4_k、TC4_k、TP4_k、TR4_k) (k ═ 1,2,3,. N); n is the number of dynamic measurements; TX4_k、TY4_k、TZ4_kRespectively representing the position coordinate three components of the receiver under the emission coordinate system; TC4_k、TP4_k、TR4_kRespectively showing three attitude angles of the receiver, such as heading, pitching and rolling under a transmitting coordinate system.

9. The condylar motion trajectory determination method of claim 8,

right condylar track:

left condylar track:

wherein, L01_kA coordinate transformation matrix for the receive frame to the transmit frame.

10. The method of claim 9, wherein the coordinate transformation matrix from the receiving system to the transmitting system is a matrix of coordinates

Wherein the content of the first and second substances,

Technical Field

The invention belongs to the technical field of medical equipment, and particularly relates to a method for determining a motion track of a condyle.

Background

In the field of oral cavity repairing specialties, modelsThe frame is an indispensable step in the diagnosis and treatment process, byThe simulation of the frame can ensure that the coordination of the form and the function is realized after the restoration made on the plaster model is brought into the mouth as much as possible. While in useIn order to obtain a simulation result that the error of the actual motion condition of the patient's oromandibular system is as small as possible, the positional relationship between the maxillary dentition and the mandibular joint can be recorded by facial arch transfer.

In the use process of the face arch, in order to obtain the condylar guidance inclination and the incisal guidance inclination, a patient needs to do various movements of the lower jaw, and firstly, the movement tracks of incisors and the condyles in the lower jaw are obtained. According to the face arch structure and the wearing mode, the face arch measuring receiver is fixedly connected with the occlusion fork, the occlusion fork is adhered to the lower dentition of a patient, namely, the central incisor is fixedly connected with the receiver, and the central incisor track can be easily obtained according to the structural parameters of the occlusion fork. For the motion trail of the condyles, the currently adopted methods are: a) acquiescent two lateral condyles and incisors in the lower jaw form an equilateral triangle with the side length of 95-140 mm; b) the angle between the default occlusion plane and the equilateral triangle is an empirical average (15-25). The original method does not consider the difference of individual patients, and has poor practicability.

Disclosure of Invention

In view of the above analysis, the present invention aims to disclose a method for determining motion trajectory of condyles, which can obtain high-precision motion trajectories of both lateral condyles.

The invention discloses a method for determining a motion track of an condylar process, which comprises the following steps:

establishing a coordinate system: establishing two sets of coordinate systems for track measurement, wherein the two sets of coordinate systems comprise a transmitting coordinate system which takes the transmitter as an origin and takes the front, the upper and the right of the transmitter as three-axis directions; a receiving coordinate system which takes a follow-up point moving along with the lower jaw as an origin and takes the front, the upper and the right of a receiver fixed at the follow-up point as three axial directions; the follow-up point keeps the positions of the right and left condyles unchanged during follow-up;

static measurement: measuring the static positions of the left and right condyles and the following point under the emission coordinate system, and calculating the position difference between the left and right condyles and the following point; performing coordinate conversion to obtain the position difference between the left and right condyles and the follow-up point under the receiving coordinate system;

dynamic measurement: measuring a series of pose data of a follow-up point which follows the movement of the lower jaw; and calculating the dynamic tracks of the left and right condyles according to the pose data and the position difference between the left and right condyles and the follow-up point under the receiving coordinate system.

Further, when the static positions of the left and right condyles are measured, the static positions of the left and right condyles are obtained by averaging after multiple measurements.

Further, when the static position measurement of the left and right condyles is performed, the head of the person remains still and the teeth are kept closed; and (3) contacting the measurement reference point of the receiver to the position of the human face condyle, and performing multiple measurements by taking the measurement reference point of the receiver as a fulcrum.

Further, the determining of the follow-up point comprises: wearing a face bow on a head of a person, installing an occlusion fork at the same time, keeping the head of the person still, adjusting the occlusion fork at a proper position, keeping teeth closed, and connecting a measurement datum point of a receiver to the other end of the occlusion fork; the point of attachment of the receiver to the bite fork is taken as the following point.

Furthermore, one end of the occlusion fork is stuck on the lower dentition and fixedly connected with the middle incisor, and forms a rigid body structure together with the condyles on the two sides.

Further, the calculation process of the position difference between the left and right condyles and the following point under the receiving coordinate system comprises;

calculating the position difference between the right condyle and the follow-up point under the emission coordinate systemDifference in position between the left condyle and the following point

Performing coordinate conversion to obtain a position difference under a receiving coordinate system;

wherein: j is 1 as the right condyle, and j is 2 as the left condyle; and L is a coordinate transformation matrix from a transmitting system to a receiving system.

Further, a coordinate transformation matrix from the transmitting system to the receiving system

Wherein the content of the first and second substances,

TC0, TP0, TR0 are heading attitude angle, pitch attitude angle, roll attitude angle of the receiver at the static position of the follower point, respectively.

Further, in dynamic measurement, the lower jaw moves forwards, backwards, leftwards and rightwards to drive a receiver fixed at a follow-up point to follow up, receive a transmitting signal of a transmitter, and obtain pose data of a series of receivers through measurement: p4(TX 4)_k、TY4_k、TZ4_k、TC4_k、TP4_k、TR4_k) (k ═ 1,2,3,. N); n is the number of dynamic measurements; TX4_k、TY4_k、TZ4_kRespectively representing the position coordinate three components of the receiver under the emission coordinate system; TC4_k、TP4_k、TR4_kRespectively showing three attitude angles of the receiver, such as heading, pitching and rolling under a transmitting coordinate system.

Further, the right condylar track:

left condylar track:

wherein, L01_kA coordinate transformation matrix for the receive frame to the transmit frame.

Further, a coordinate transformation matrix from the receiving system to the transmitting system

Wherein the content of the first and second substances,

the invention can realize at least one of the following beneficial effects:

the method can determine the motion trail of the condylar process, does not depend on an equilateral triangle and an included angle between the triangle and the occlusal surface under the assumed condition, and has the advantages of individuality and practicability. In addition, the invention can obtain a more accurate track curve, and lays a foundation for further solving the condylar guidance and resection guidance parameters.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

Fig. 1 is a flowchart of a condylar motion trajectory determination method in the present embodiment;

FIG. 2 is a coordinate system relationship diagram in the present embodiment;

FIG. 3 is a comparison of the antero-lateral right condylar track (sagittal plane) in this example;

fig. 4 is a comparison of the antero-lateral left condyle track (sagittal plane) in this example.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.

The embodiment discloses a method for determining a motion trajectory of an condylar process, which performs position measurement by adopting a mode that a transmitter transmits a detection signal and a receiver receives the detection signal, and the specific method comprises the following steps as shown in fig. 1:

step S1, coordinate definition: establishing two sets of coordinate systems for track measurement, wherein the two sets of coordinate systems comprise a transmitting coordinate system which takes the transmitter as an origin and takes the front, the upper and the right of the transmitter as three-axis directions; a receiving coordinate system which takes a follow-up point moving along with the lower jaw as an origin and takes the front, the upper and the right of a receiver fixed at the follow-up point as three axial directions; the follow-up point keeps the positions of the right and left condyles unchanged during follow-up;

specifically, as shown in fig. 2, a relationship diagram between a transmitting coordinate system (denoted by T) and a receiving coordinate system is shown, and for clarity, a transition coordinate system (denoted by T') is added to the relationship diagram between the coordinate systems;

emission coordinate system definition T: the three axes are defined as X1, Y1, Z1, with the origin at a fixed point or center point of the transmitter used to transmit the measurement signal, with X1 pointing forward (i.e., the direction in which the transmitter transmits the signal), Y1 pointing upward, and Z1 pointing to the right, relative to the transmitter.

The transition coordinate system is defined as T': three axes are defined as X1 ', Y1 ' and Z1 ', the origin is at the following point moving along with the mandible, and the three axes are respectively parallel to three axes of a T emission coordinate system; the follow-up point keeps the positions of the right and left condyles unchanged when moving along with the mandible.

The receive coordinate system is defined as R: three axes are defined as X2, Y2 and Z2, the origin is at the following point so as to be fixed at the following point, and the front, the upper and the right of a receiver for receiving measurement signals are three axes directions; i.e., X2 points to the front of the receiver (i.e., the direction in which the receiver receives signals), Y2 points upward, and Z2 points to the right.

The definition of points in fig. 2, in the emission coordinate system, P1, P2, P3 and P4 mean and are expressed as follows: p1: the right condyle P1(TX 1; TY 1; TZ 1);

p2: the left condyle P2(TX 2; TY 2; TZ 2);

p3: middle incisor position P3(TX 3; TY 3; TZ 3);

p4: the servo point position P4(TX 4; TY 4; TZ 4).

Step S2, static measurement: measuring the static positions of the left and right condyles and a follow-up point under a transmitting coordinate system, wherein the follow-up point moves along with the lower jaw and keeps the positions of the follow-up point and the right and left condyles unchanged; calculating the position difference between the left and right condyles and the follow-up point; performing coordinate conversion to obtain the position difference between the left and right condyles and the follow-up point under the receiving coordinate system;

the method specifically comprises the following steps:

step S201, measuring static positions of two condyles of a right condyle P1 and a left condyle P2;

during measurement, the human head is kept still, and the teeth are kept closed.

The receiver is horizontally placed, so that the measurement reference point of the receiver is contacted with the position of the condyle of the human face (the position of the condyle can be determined by touching with hands), the reference point is taken as a fulcrum (the contact point of the vertex and the position of the condyle is kept unchanged), the receiver is moved left and right, up and down, laterally rolled and the like to receive the signal emitted by the emitter, and the setting of the reference point of the receiver enables the position measurement to be more accurate.

When measuring the right condyle, one set of data can be obtained, which is recorded as:

P1(XP1_i、YP1_i、ZP1_i)(i＝1,2,3,...,n)

wherein: XP1, YP1 and ZP1 respectively represent three components of position coordinates of right condyles in a emission coordinate system in a static state; i 1,2, 3.., n, indicating that n values were measured there.

When measuring the left condyle, one set of data can be obtained, which is recorded as:

P2(XP2_j、YP2_j、ZP2_j)(j＝1,2,3,...,m)

wherein: XP2, YP2 and ZP2 respectively represent three components of the position coordinates of the left condyle under a launching coordinate system in a static state; j-1, 2, 3.., m, indicating that m values were measured there.

Respectively calculating and averaging the measured values of the right and left condyles to obtain the static positions of the right and left condyles in the emission coordinate system:

p1: right condyle process

P2: lateral condyle process

Step S202, measuring the static position of the follow-up point;

specifically, the determining of the follow-up point comprises the following steps: the face bow is worn on the head of a person, an occlusion fork is installed at the same time (one end of the occlusion fork is stuck on a lower tooth column, namely, the occlusion fork is fixedly connected with middle incisors and forms a rigid structure with condyles on two sides), the head of the person is kept still, the occlusion fork is adjusted to be at a proper position, teeth are kept closed, and a measuring reference point of a receiver is connected to the other end of the occlusion fork. The point of attachment of the receiver to the bite fork is taken as the following point.

Measuring the signals transmitted by the transmitter at the static position receiver to obtain the static position information of the follow-up point P4 and the attitude information of the receiver;

position information and three attitude angles of the receiver relative to the heading, pitch and roll of the transmitting coordinate are recorded as P4(TX40, TY40, TZ40, TC0, TP0 and TR 0); TX40, TY40 and TZ40 respectively represent three components of coordinates of a following point P4 in a static state and emission coordinate system; TC0, TP0 and TR0 respectively represent three attitude angles of heading, pitch and roll.

Step S203, calculating the position difference of the condyles P1, P2 and the following point P4 in the emission coordinate system, respectively.

Step S204, performing coordinate conversion to obtain the position difference between the left and right condyles and the follow-up point under the receiving coordinate system;

the method specifically comprises the following steps:

1) coordinate translation is carried out to obtain the position difference of a transition coordinate system T';

is calculated under a transmitting coordinate system T, and because the T 'coordinate is parallel to the T coordinate, under a transition coordinate system T' can be obtained through translation,and is not changed.

2) Rotating the coordinates to obtain a position difference under a receiving coordinate system R;

wherein: j ═ 1 is the right condyle, and j ═ 2 is the left condyle.

L is a coordinate transformation matrix from a transmitting system to a receiving system, and specifically comprises the following steps:

step S3, dynamic measurement: measuring a series of pose data of a follow-up point which follows the movement of the lower jaw; and calculating the dynamic tracks of the left and right condyles according to the pose data and the position difference between the left and right condyles and the follow-up point under the receiving coordinate system.

The method specifically comprises the following steps:

1) the lower jaw moves forwards, backwards, leftwards and rightwards to drive a receiver fixed at a follow-up point to follow up, receive a transmitting signal of a transmitter, and obtain a series of measurement numbers of receiver poses by measurement:

P4(TX4_k、TY4_k、TZ4_k、TC4_k、TP4_k、TR4_k) (k ═ 1,2,3,. N); and N is the number of dynamic measurements.

2) Calculating the dynamic condylar track;

right condylar track:

left condylar track:

wherein L is_o1The method is characterized in that a coordinate transformation matrix from a receiving system to a transmitting system specifically comprises the following steps:

by adopting the method of the embodiment, the actually measured left and right condylar tracks are shown in fig. 3-4:

as can be seen from comparison of fig. 3 to fig. 4, when the method according to the embodiment is used for calculating the condylar trajectory, a more accurate trajectory curve (compared with the trajectory curve of zebris) can be obtained, and a foundation is laid for further solving the condylar guidance and resection parameters.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.