JPH0140497Y2 - - Google Patents

Description

[Detailed description of the invention] This invention improves the image quality of a dental full-mouth X-ray panoramic imaging device and improves its diagnostic accuracy. The present invention relates to a measuring device that accurately measures the unique orbit prior to photographing in order to input shape information into the device.

In general, a dental full-mouth X-ray panoramic imaging device (hereinafter referred to as a panoramic device) has an X-ray source at one end of an arm and a film advance mechanism at the other end, which are placed facing each other across the subject. The film is rotated along a certain dental arch and the film is moved in the opposite direction to the rotation to take a panoramic tomographic image of the dental arch. The sharpness of a panoramic dental image taken by such an apparatus is determined by how well the rotation trajectory curve of the arm matches the dental arch tomographic trajectory curve of the subject. However, conventionally, with this device, the patient's dental arch trajectory is known and images are taken using a standard trajectory curve. Accurate X-ray information cannot be obtained due to lack of sharpness or distortion, and there are many retakes, which not only causes time loss but also increases the patient's exposure dose. There are several methods that have been used in the past to prevent this, the first of which is a matrix plate that is inserted into the subject's oral cavity and engaged with it, and is equipped with multiple pressure contacts. This method uses an element to detect the patient's unique dental arch trajectory from the contact position activated by the occlusal pressure, and uses this detection signal to control arm rotation and film movement in real time. 2 is a preprocessing method in which a matrix plate similar to the above is placed in the subject's occlusion prior to imaging, its unique trajectory is measured, and the measured data is set in a panoramic device to perform imaging. However, the occlusion of the matrix plate described above not only causes considerable pain to the patient, but the shape of the tooth row detected by this method is that of the tips of the teeth, and not the desired arch shape of the center of the tooth root. Necessary data cannot be obtained when there is a significant difference in shape between the former and the latter, such as in humans. Furthermore, if the tooth root remains but the tooth is missing, it is necessary to infer the data of the missing part from the adjacent teeth, which makes the detection control means complicated.
Furthermore, if there are multiple missing teeth, it becomes impossible to recognize the shape. In addition, there are a number of drawbacks, such as the fact that for patients with painful teeth, occlusion with a matrix plate may cause severe pain, making it impossible to use the matrix plate.
As a method that does not use the above-mentioned matrix plate, a molding material such as plaster or wax sheet is used.
There is a preprocessing method that copies the unique dental arch shape and measures the dental arch data, but it complicates the operator's work and
Not only is it time-consuming and labor-intensive, but it also has the disadvantage that it is difficult to sterilize and sterilize the mold, which is necessary for hygiene control, and that the mold material cannot be reused.

This invention eliminates the drawbacks and problems of the conventional ones, and provides a dental tomography trajectory measuring device that is simple in structure and operation, and can quickly and accurately measure without causing pain to the examinee. With the goal.
That is, a pair of rod-shaped measuring rods each having one end pivoted to a fulcrum shaft are biased into a V-shaped opening via an elastic body such as a compression spring, and the X-axis coordinate on the intraoral plane of the subject is biased. The legs of the measuring rod are opened in a V-shape at the top, and a tooth row contactor is provided which abuts the inner surface of the tooth row at the tip of the open leg of the measuring rod and is slidable or rolling along the tooth row. is provided with a fulcrum shaft guide mechanism that supports the fulcrum shaft movably in the Y-axis direction perpendicular to the X-axis, and means for detecting the movement distance of the fulcrum shaft and the measuring rod opening angle, and the relationship between the moving position and the opening angle of the rod is provided. This invention relates to a dental tomographic trajectory measuring device characterized in that it measures the shape of a dental arch.

This idea will be explained below using the drawings. Figure 1 is a plan view of a direct reading type tooth row tomographic trajectory measuring device as an embodiment of this invention. Figure 2 is the -' of Figure 1.
FIG. In the figure, the device 1 is a V-shaped 1
Pair of measuring rods 2A, 2B and measuring rod pivoting fulcrum shaft 3
and a fulcrum guide mechanism 4, and an index 5.
A fulcrum position detection mechanism 7 consisting of a moving distance display scale 6 engraved on the base of the guide mechanism 4, and a heat-resistant transparent synthetic resin plate or glass plate fixed to the fulcrum shaft 3, for example. For example, the angle scale 8S is engraved in 1° increments (the figure is shown in 5° increments for simplicity), which is engraved on both the front and back sides of a 2 mm thick angle scale plate 8, for example, to prevent parallax errors (reading errors). One index line 9 carved in the center of the same transparent member part of the left measuring rod 2A and the same index line 10 of the right measuring rod 2B.
A measurement rod opening angle detection mechanism 11 is provided. The figure shows a state in which measurement of the mandibular tooth row tomographic trajectory 12 is started for the subject, and a rotatable tooth row contactor 13 is attached to the tip of the measuring rod 2 to attach the left and right second molars 14, 14'. is in contact with the inside of the Measuring rod 2
A and 2B are engaged with the pivot fulcrum shaft 3, and are moved on the coordinate X axis on the intraoral plane by the elastic force of the spring 15 that urges one end 2AT and 2BT of the measuring rod in opposite directions. The legs are opened in opposite directions (arrows a and b), and the contact 13 is pressed against the inner surface of the tooth row with appropriate pressure. 16 and 16' provided in the middle of the measuring rod are measuring rod connectors, and when measuring the maxillary dentition, the tips 2AP and 16' of the measuring rod are connected to each other.
This is to change the contactor 13 to the dotted line position 13' in Figure 2 by replacing the contactor 2BP.By changing the orientation of the contactor 13 by 180° in this way, the
The upper and lower tooth rows can be easily measured in the state shown in the figure. In addition, a shock absorber 17 such as a rubber plate is attached to the tip of the fulcrum guide mechanism 4.
By joining and contacting the surface of the subject's lips 18, the horizontal midline 20 and the central axis 1C of the device 1 are aligned.
The accuracy of measurement can be ensured by matching the values.
Furthermore, a pair of leg-opening regulating stoppers 19 for regulating the opening of the measuring rod are installed at the tip of the guide mechanism 4. In the above configuration, the current fulcrum movement distance l
is read as α A and α B using the index 5 and the display scale 6, and the leg opening angle is read as α _A and α _B with respect to the horizontal plane midline 20 using the angle scale plate 8 and the respective indexes 9 and 10, the contact 13 is read. Since the distance L between the axial center position and the axial center position of the measuring rod fulcrum 3 and the radius of the contactor 13 are known, an elliptical curve that approximates the tooth row fault trajectory 12, that is, a curve connecting the tooth row inner surface contact points, can be obtained. Can be measured. Figure 3 shows the coordinates that _explain this.The intersection of the above coordinates Set the point on the X axis to −X, and α _B
If the point is set to +X, the coordinates of the tooth contact points 1A and 1B can be found. For example, by adding 1/2 of the thickness diameter of each of the second molars to this, the left and right starting point positions 12-1A, 12- of the tooth row fault trajectory 12 are obtained.
1B is found. Continuing, the operation knob 21 of the fulcrum guide mechanism 4 is gradually moved in the direction of the arrow C, and the fulcrum position Y and α _A , α _B are respectively measured up to the front teeth where the contacts 13 touch each other, thereby obtaining the position shown in FIG. 3. A trajectory approximation curve 22 shown by a dotted line is obtained, and by adding corrections for each tooth to this curve, a dental tomographic trajectory curve 12 unique to the subject can be measured. In this way, the trajectory of the tooth row can be determined by simply lightly abutting the contactor 13 against the inner surface of the tooth row, thereby eliminating the pain of matrix plate occlusion for patients suffering from toothache.

The above is the structure and operation of the direct display type device, and next, a tooth row trajectory coordinate calculation and display type device will be explained as another embodiment of this invention with reference to FIG. The figure is a block diagram showing the elements of its configuration.
A, 2B, their pivot fulcrum shafts 3, and fulcrum guide mechanisms 4 have almost the same structure as in FIGS. 1 and 2, but
The fulcrum position detection and angle detection mechanism is not an indicator scale type, but has three potentiometers 26 for fulcrum distance detection shown by dotted lines inside the fulcrum housing 25, and α _A
Angle detection 27, α _B angle detection 28, and respective detection circuits 29, 30, 31 coupled thereto.
It is composed of: Among these detection signals, S _B is sent to the left tooth row contact position coordinate calculation circuit 32,
S _A is also input to the calculation circuit 33 on the right tooth row side,
S _P , that is, the fulcrum position signal is input to both circuits 32 and 33 mentioned above. Therefore, the above 32 calculation circuits calculate the coordinate signal S _L ′, that is, +X′, Y′ that approximates the right half of the trajectory approximation curve 22 shown in FIG. 3, that is, the left tooth row of the subject. The correction circuit 34
Output to. Similarly, the arithmetic circuit 33 outputs -X' and Y', which approximate the right tooth row of the subject, to the correction circuit 35 as S _R ' signals. The correction circuits 34 and 35 respectively correct the thickness and diameter of the different teeth at the Y coordinate, and obtain the signals S _L , S of the coordinates +X/Y and -X/Y of the tooth row tomographic trajectory 12 unique to the subject to be examined. _R is output and printed by the printer 36. In this way, this device does not require reading the position and angle via a scale, and the data of the dental tomographic trajectory is automatically printed out, speeding up the measurement.

The above are two embodiments of this invention, but this invention is not limited to the illustrations and explanations; for example, the tooth row contactor may be a sliding element instead of a rolling element, and a pivot fulcrum mechanism or a sliding element may be used. Various fulcrum guide mechanisms can be considered, and it is also easy to digitally display the electrical detection signal as it is. Furthermore, the signals after the detection circuit shown in FIG. 4 may be either analog signals or digital signals.

This idea is structured as above, so
When performing dental tomography using a dental X-ray panoramic device, the drawbacks and problems of conventional devices and methods for detecting the patient's unique dental arch trajectory are eliminated, and this method is particularly useful for patients suffering from tooth pain. Suitable for accurately measuring the dental trajectory without causing pain, it has a simple structure, can be completely sterilized, and can be quickly measured with easy operation. This provides a convenient device that contributes to diagnostic performance.

[Brief explanation of the drawing]

Fig. 1 is a front view of an indicating scale type tooth row tomographic trajectory measuring device which is the first embodiment of this invention, Fig. 2 is a -' side sectional view of the above device, and Fig. 3 is a tooth row tomographic trajectory curve. The XY coordinate diagram and FIG. 4 are block diagrams showing the circuit configuration of a coordinate calculation display type tooth row tomographic trajectory measuring device which is a second embodiment of the invention. 2A, 2A... A pair of measuring rods, 3... Fulcrum shaft,
4... Fulcrum guide mechanism, 7, 26, 29... Fulcrum position detection means, 11, 27, 28, 30, 31...
Measuring rod opening angle detection means, 12...Tooth line fault trajectory, 13...Tooth line contactor, 15...Measuring rod opening leg biasing elastic body, l...Movement distance of fulcrum shaft, α _A , α _B …
...Right/left leg angle with respect to the midline 20, S _P ...Electrical signal of fulcrum movement distance, S _A , S _B ...Electrical signal of leg angle, 32, 33, 34, 35, 36... Trajectory measurement Value calculation display means.

Claims (1)

[Claims for Utility Model Registration] 1. One end of each is pivotally attached to a fulcrum shaft, and the legs are energized by the elastic force of the elastic body, and can be freely opened in a V-shape on the coordinate X axis in the patient's oral cavity. a pair of measuring rods,
At the tip of each open leg of this measuring rod, a tooth row contactor is provided which is in contact with the inner surface of the tooth row and can slide or roll along the tooth row, and the fulcrum axis is perpendicular to the X axis. A fulcrum guide mechanism that supports the fulcrum shaft movably in the Y-axis direction, fulcrum position detection means for detecting the moving distance of the fulcrum shaft, and angle detecting means for detecting the opening angle of the measuring rod are provided. A dental arch tomographic trajectory measuring device characterized in that the shape of the dental arch is measured based on the relationship with the leg angle. 2. The dental arch tomographic trajectory measuring device according to claim 1, wherein the means for detecting the fulcrum movement distance and the measuring rod opening angle is a mechanism for directly indicating a scale using an index. 3. The dental arch tomographic trajectory measuring device according to claim 1, wherein the means for detecting the fulcrum movement distance and the measuring rod opening angle is a signal detector and a detection circuit. 4 Calculate the moving distance and angle detection signals,
A dental arch tomographic trajectory measuring device as set forth in claims 1 and 3, further comprising calculation display means for outputting and displaying measured values as XY coordinates.