JPH046742Y2 - - Google Patents

Description

[Detailed explanation of the invention] (1) Industrial application field This invention is a full-jaw dental device that can take panoramic photographs of not only the dentition area but also the oral function and facial area including the upper and lower jaws. Regarding the X-ray imaging device, in detail, it is equipped with multiple tomographic trajectories, and
The present invention relates to a device that detects a dental and jaw region tomographic trajectory unique to a subject and selects a corresponding tomographic trajectory.

(2) Prior art In general, the sharpness and resolution of a panoramic photograph of a dental full-mouth X-ray imaging device (hereinafter referred to as a panoramic device) are determined by the rotation trajectory curve of the X-ray receiving surface and the tomography of the patient's teeth and jaw area. It depends on how well it matches the trajectory curve. However, with conventional panoramic devices, the tomographic trajectory curve of the dental and jaw area is known for all subjects, regardless of their age or facial features, and the image is taken using a standard pseudo-elliptical trajectory curve. It is customary. Therefore, in the case of a subject, such as a child, whose trajectory differs from the standard trajectory curve, the image of the area that deviates from the standard trajectory may lack clarity or be distorted, making it difficult to obtain accurate X-ray information and positioning. There are many cases in which images must be retaken to make corrections, which results in an increase in the patient's exposure dose.
In order to prevent this, a method can be considered in which the unique trajectory of any subject is unknown, this is detected, and the tomographic trajectory on the device side is controlled to match the detected unique trajectory. It is carried out in the department.
For example, the method disclosed in Japanese Patent Publication No. 56-136500 uses an element called a matrix plate, which is equipped with a plurality of pressure contacts, which is inserted into the mouth of the subject and brought into occlusion, and the contact positions are activated by the occlusal pressure. The patient's unique dental arch trajectory is detected from the subject, and the arm rotation and film movement of the panoramic device are controlled in real time based on this detection signal. However, the above-mentioned matrix plate has a wide occlusal area, for example, 5 to 6 cm in width, and it causes considerable pain to the subject to have to insert it into the entire oral cavity and engage it until the end of the imaging process. In addition, there is a problem that the circuits and mechanisms for dental arch data processing and real-time control are complicated and expensive. In addition, the conventional method of detecting unknown tomographic trajectories of a subject through pre-processing operations prior to panoramic imaging is to place a mold material such as plaster or wax sheet into the subject's unique This is a method of copying the dental arch shape, measuring the dental arch data, and setting it on a panoramic device. This method not only complicates the operator's work and requires time and effort, but also has the disadvantage that it is difficult to disinfect and sterilize, which is necessary for hygiene control, and the mold material cannot be reused. Furthermore, the method of using a matrix plate as described above in the preprocessing operation has the advantage of being sterilizable and reusable, and allowing accurate detection of dental arch data with high precision, but on the other hand, it requires a large amount of measurement data and the associated data processing There are problems in that the detection device is large-scale and expensive.

(3) Purpose This device eliminates the shortcomings and problems of the conventional panoramic device described above, and detects the unique tomographic trajectory shape of the dental and jaw region of the patient with a simple configuration and easy operation. To provide an inexpensive and convenient device that can easily obtain tomographic images with high sharpness and excellent diagnostic accuracy by selectively selecting and photographing tomographic trajectories corresponding to .

(4) Configuration The panoramic device according to this invention is not much different from conventional devices in terms of its principle of tomography and basic configuration. The first configuration, which is very different and is the main part of this idea, is to divide all of the tooth and jaw region tomographic trajectories, which have different shapes for each subject, into multiple types, such as large, standard, and small, extra-large, large, and standard. Shape/Small/
A plurality of tomographic trajectory imaging means corresponding to this classification, that is, a digital control means that variably controls the feeding speed of the cassette in accordance with the rotational phase of the arm, for example, stores a plurality of speed characteristics. This is a configuration that allows selection.
Next, the second configuration is a means for detecting the tooth-and-jaw region tomographic trajectory shape unique to the subject through a preprocessing operation, and selecting the plurality of tomographic trajectories based on this detection. The former detection has the functions of a caliper and a deep stage, for example, and uses a special detector devised to measure the distances A and B shown below to measure the distance A between the left and right canine teeth of the subject, and both. Simultaneously measure the distance B from the straight line connecting the canines to the anterior edge of the central incisor, and use these measured values A and B.
The dental arch arc R formed by each of the above teeth is expressed as follows (1)
The unique tooth and jaw area tomographic trajectory shape is detected by using the formula. R=4B ² +A ² /8B...(1) As a means of selecting multiple fault trajectories preset in the above device based on the detected characteristic trajectory shape, it is possible to Either the values A and B are collated, or the measured values A and B of the distance measuring device are outputted as electrical signals, and this signal is processed to select a trajectory. The above is the structure of this idea.

(5) Examples Examples of this invention will be described below using the drawings. 1 and 2 are diagrams illustrating the principle of detecting the tomographic trajectory of the tooth and jaw region in the apparatus according to the embodiment of this invention, and FIG. 1 is a diagram illustrating the same using the lower jaw 1 as an example. The dental arch, that is, the arc-shaped curve formed between the left and right molars 2, 2' is the anterior dental arch curve formed by the canine teeth 3, 3', the lateral incisors 4, 4', and the central incisors 5, 5'. 6, and molar tooth arches 7, 7' (shown by dashed lines) having a large radius of curvature from the canine teeth 3, 3' to the molar teeth 2, 2'. This molar dental arch 7,
Each tooth belonging to 7' has a wide fault width in the panoramic device at that part, so the fault trajectory is, for example, a straight trajectory 8,8' connecting the canine centers 3C, 3C' and the molar centers 2C, 2C' with a straight line. A good tomogram can be obtained even if the image is taken as Furthermore, the left and right temporomandibular joints 9,
Similarly, good photographs can also be obtained in the case of 9' due to the linear trajectories 10 and 10' extending outward by an anatomically determined predetermined angle θ with respect to the linear trajectories 8 and 8'. However, the aforementioned anterior tooth row 3,
3' to 5,5', the cross section width of the device is narrow, and the tooth thickness and diameter are thinner, and the dental arch curve 6 differs for each subject, so the curve 6 can be unique to each subject. Sharp tomographic images cannot be obtained unless the fault trajectories that match exactly are taken. The anterior dental arch 6 is measured accurately and quickly without causing any pain to the subject, and from this measurement value, the dental arch for the upper jaw and the jaw area for the lower jaw are determined, respectively. One of the main parts of this invention is to detect the fault trajectory shape unique to each subject.

The dental arch arc 6 has a distance A between the left and right canine centers 3C and 3C', and an intersection point 5F where the straight line 3S connecting these 3C and 3C' and the horizontal midline 11 intersect with the dental arch arc 6.
By measuring the distance between B and B, the radius of curvature R of the dental arch 6 can be determined geometrically using the following equation (1).

R=4B ² +A ² /8B ...(1) Figure 2 shows three examples of the radius of curvature R determined by the above formula (1), and shows the tooth row formed by A ₁ and B ₁ . R ₁ of the arch is small, and even if B ₁ is the same, A becomes A _2. R ₂ of the dental arch is larger than R ₁ , and R ₃ and R ₂ of the dental arch of A ₃ and B ₂ . It becomes even bigger. In this way, by detecting the shapes of many anterior dental arch arches 6 that differ for each arbitrary subject as a function R of two variables A and B, it is possible to detect The straight line trajectories 8, 8' and 10, 10' shown can also be detected. FIG. 3 is a diagram showing the shapes of, for example, three types of dental and jaw region fault trajectories 12A, 12B, and 12C that are preset in the panoramic device of this invention. The fault trajectories of all subjects except
They are classified into medium and small, and therefore almost all unique orbits either match these three types or are included in a very close approximation. In that case, the width X and depth Y of the track are also included. As can be seen from the figure, the radius of curvature R of the orbits 12A, 12B, and 12C satisfies R _A > R _B > R _C. The above radius of curvature R
is said to be in the range of approximately 15 mm to 30 mm, and the panoramic device of this invention is set to allow selection of three types of dental and jaw region tomographic trajectory imaging functions centered on R within the above range. . The setting of these multiple cut-off trajectories and their imaging means are described in detail in the specification of the patent application No. 179963/1983, ``Dental multi-orbit tomography apparatus,'' which the authors filed earlier. is omitted. 4 to 6 are diagrams showing the structure of a direct reading type detector 13A as a first embodiment of the dental arch detector of this invention to which the above principle is applied. Fourth
The figure is a plan view of the subject's front teeth being measured by the detector 13A, FIG. 5 is a sectional view on the -' side of FIG. 4, and FIG. 6 is a front view of the detector. It is. In Fig. 4, the dental arch detector is placed in contact with the tip of the left and right canine teeth 3, 3' of the subject's lower jaw 1 at the boundary line between the teeth and the gingiva, and at a point corresponding to their centers 3C, 3C'. These are the A probe fixing claw 14T and the A probe sliding claw 15 of 13A. The A probe fixing claw 14T is formed in a part of the base 14 which is integrated with the detector 13A. This base 1
An upper cover 16 and a lower cover 17 are connected to each other by screws 18, and a fixed shaft 19 is supported at the center thereof. A pair of rotary scale plates A and B2 rotatably supported on this fixed shaft 19
1 and 22 are integrated with pinions 23 and 24, respectively, and have a scale 25 for distance A and a scale 26 for distance B on their peripheries, and are knurled to facilitate rotation. Reference numeral 27 denotes a distance display section having a notch in the cover and the base so that the scale can be read by an indicator 28 on the upper cover. The base 14 has long guide holes A and
B29, 30 are provided, and one long hole A29
The sliding member A31, which is made and fitted together, has the aforementioned A probe sliding claw 15 on one end and the sliding member A31 on the other end.
It is attached to a sliding pawl 33 provided with 32. With this configuration, rotation of the rotary plate A21 in the direction of arrow a results in sliding of the A probe sliding claw 15 in the direction of arrow b, and the measured value of distance A is directly indicated. Next, the first
Although the distance B shown in the figure is A probe 14T,1
5 cannot contact the centers 3C, 3C' of the left and right canines 3, 3', and therefore the straight line 3S is located in front of the straight line 3S connecting 3C, 3C' by (△L) (about half the distance of the canine tooth thickness). ', so while maintaining this contact, rotate the rotary plate B22 of the detector 13A in the direction of the arrow C, and slide the B probe sliding piece 35 in the direction of the arrow d to move it inside as shown in the figure. The distance B is directly read from the scale 26 of the rotary plate B22 by contacting the boundary line between the teeth and the gums of the incisors 5, 5'. The B probe sliding piece 35 slides in the d direction through the guide slot B3.
0, a rack B37 which is integral with this, and a pinion 24 of the rotary scale plate B are used in the same manner as in the case of the A-probe sliding claw 15. As shown in FIG. 4, the A-probe sliding claw 15 and the B-probe sliding piece 35 are set at an elevation angle or depression angle so that their tooth contact portions coincide with the A-probe fixing claw 14T. Although not shown, each tooth contacting part is covered with, for example, a transparent plastic bag and replaced with a new bag for each subject to ensure perfect hygiene.

FIG. 7 is a trajectory selection diagram in which the aforementioned three representative tomographic trajectories set in the panorama device can be selected by simply comparing the distances A and B measured by the direct reading detector 13. In FIG. 40, the horizontal axis is the measured value Amm, the vertical axis is the measured value Bmm, and the quadratic characteristic curves C ₁ , C ₂ , C ₃ , and C ₄ are obtained by dividing the range of the radius of curvature R into three. , Therefore, for example, three types of fault trajectories preset in the device are a zone Z 1 surrounded by characteristics C ₁ and C ₂ , a zone Z ₂ surrounded by C ₂ and C ₃ , and a zone Z ₂ surrounded by C ₃ and C ₄ . The enclosing swath Z is ₃ ,
For example, the value measured by the detector 13 is A',
If B', then the intersection R' is in the above _Z1 area, and the minimum trajectory shown in FIG.
Select the fault trajectory of R _C. Therefore, the measured value A,
Just by finding out in which area the intersection of B is located, it is possible to immediately select the trajectory of the device. This diagram 4
0 is pasted on the upper and lower covers 16, 17 of the direct reading detector 13A, the measurement and selection operations can be performed very easily and quickly.

Next, the operator only measures A and B,
A second embodiment of this invention in which trajectory selection is automated will be described. 8 and 9 are diagrams showing the configuration of the dental arch detector 13B of the automatic selection type device, and FIG.
This figure is a plan view showing the internal structure of a detector 13B, which has almost the same structure as the direct-reading detector 13A shown in FIGS. 4 to 6, with its upper cover 16 and rotary plate A21 removed. Components with the same symbols as those in FIGS. 4 to 6 will not be described in detail. It has a rotating plate 21 shown by a dashed line and a rack A32 that meshes with the pinion 23 integrated therewith at one end, and an A probe sliding claw 15 for measuring the distance A at the other end, along the elongated guide hole A29. A contact drive plate A42 made of a metal member is screwed to a sliding piece 33 made of plastic, for example, which slides in the direction of arrow b. This contact drive plate A42 is arranged so that its tip 42 does not come into contact with the rack A32.
Potentiometer A4 fixed to base 14 at T
It is combined with the movable contact of 3. In this way, a constant voltage is applied to both terminals 44 and 45 of potentiometer A43, and, for example, terminal 4 of contact drive plate A42 is applied.
If 6 is the output terminal, the voltage signal corresponding to distance A
V _A is output. Therefore, neither the rotary plate A21 nor the rotary plate B22 described below requires a scale. Next, FIG. 9 is a rear view showing the internal structure with the lower cover 17 and rotating plate B22 removed. A contact drive plate B48 made of a metal member similar to the above is screwed to the base of the B probe sliding piece 35 made of an electrically insulating material similar to the above, and its tip 48T is attached to the base 1.
4 is connected to the movable contact of potentiometer B49 fixedly attached to B49. With this configuration, the voltage signal _VB corresponding to the distance B measured by sliding in the direction of the arrow d is applied to the terminal 5 of the contact drive plate 48 of the potentiometer 49.
Output from 0. FIG. 10 is a block diagram of a signal processing circuit that processes the V _A and V _B signals and selects a trajectory corresponding to the individual trajectory of the subject from a plurality of tomographic trajectories. The potentiometer A is detected by the operator's measurement operation using the signal output type detector 13B.
The analog signal V _A output from the potentiometer B 43 and the analog signal V _B from the potentiometer B 49 are connected, for example, by an electric line and are input to the A/D converters 52 and 53 in the panoramic device 51 surrounded by a two-dot chain line. The signals are then converted into digital signals S _A and S _B , respectively.
These S _A and S _B signals are input to the arithmetic circuit 54, where the arithmetic processing of equation (1) described above is performed, and the signal corresponding to R is
_SR is output. This S _R corresponds to the intersection R of the A scale and B scale explained in FIG. 9, and when this S _R is input to the track selection circuit 55, Z ₁ , Z ₂ , Z ₃ in FIG.
Determine which fault area it belongs to and select it. This discrimination signal S _K is transmitted to the trajectory selective film advance control mechanism 56 surrounded by a dotted line. Starting from the address designation signal, a panoramic image is taken of the tomographic trajectory designated by the discrimination signal S _K using a mechanism that variably controls the film feed speed according to the rotational phase of the arm. In this way, the operator can automatically select a tomographic trajectory that matches the patient's unique dental and jaw region trajectory by simply measuring the patient's anterior teeth using the detector 13B. This is a second embodiment of this device.

The above is the first and second embodiments of this invention, but it goes without saying that this invention is not limited to the illustrations and explanations. For example, the dental arch detector 13A,
The configuration of 13B may be any configuration as long as distances A and B can be measured accurately, and the number of tomographic trajectories set in the apparatus is not limited to three types, but three or more types may be provided. Furthermore, the signals at distances A and B from the dental arch detector 13B do not necessarily need to be transmitted to the panoramic device via an electric line; for example, they may be transmitted optically using an optical fiber, or by using ultrasonic waves. There are also other means of transmitting the information, all of which belong to the scope of this invention. The selectable multi-orbit tomography means is not limited to the one described in Japanese Patent Application No. 179963/1982. For example, the number of revolutions of an arm rotation motor is detected, this detection signal is converted by a predetermined conversion coefficient, and the Therefore, it can also be applied to a panoramic device in which the film feed motor is controlled.

(6) Effects Since this device is constructed as described above, it does not cause any pain to the examinee, detects the unique shape of the tooth-maxillary region fault trajectory through simple and quick operations, and detects the shape of the tomographic area in advance. From among the plurality of trajectories of the panoramic device, which is equipped with selectable representative fault trajectories that classify the fault trajectories of all the subjects, the one that matches the detected shape is selectively selected using a diagram. The present invention provides an inexpensive and convenient device that can easily select and photograph panoramic images with excellent sharpness and resolution, and with high diagnostic accuracy.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the principle of tooth-jaw region tomographic trajectory detection according to this invention, Figure 2 is a schematic diagram showing the relationship between the distances A and B of the anterior dental arch and the radius of curvature R, and Figure 3 is this invention. This is a schematic diagram showing, for example, three types of fault trajectory shapes that can be selected on the panoramic device of A plan view of the direct-reading dental arch detector of the device according to the first embodiment of the invention and a diagram of the state of measurement by this detector, FIG. 5 is a cross-sectional view on the -' side of FIG. A front view of the display side, FIG. 7 is a trajectory selection diagram pasted on the detector, and FIG. 8 is a distance A of the dental arch detector of the automatic trajectory selection type panoramic device according to the second embodiment of this invention.
FIG. 9 is an internal plan view showing the configuration of the signal output section, FIG. 9 is a rear view showing the configuration of the distance B signal output section of the detector, and FIG. 10 is a circuit block diagram of the automatic trajectory selection type panoramic device. 1... Subject's lower jaw, 3, 3'... Left and right canines, 3S... A straight line connecting the left and right canines, 5, 5'...
...Central incisors, 6... Anterior dental arch, A... Distance between left and right canines (mm), B... Distance from the straight line connecting both canines to central incisors 5 and 5' (mm), R ...Radius of curvature (mm) of 6 above, 8, 8', 10, 10'...Tooth-jaw area fault trajectory excluding the area between the left and right canines above, 12A...Fault trajectory with radius of curvature (R _A ) (large size ), 12B... Fault trajectory (medium size) with radius of curvature (R _B ), 12C...
Fault trajectory (small) with radius of curvature (R _C ), 13A...
... Direct reading type dental arch detector, 13B... Signal output type dental arch detector, 40... Trajectory selection diagram for direct reading type dental arch detector, 42, 43... Distance A signal output section of the above 13B, 48 , 49... Distance B signal output section of the above 13B, 52, 53, 54, 55... Signal processing circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A horizontal arm in which an X-ray source and a cassette are disposed facing each other with the head of the subject in between is rotated around the patient's head, and This device uses a moving cassette to capture panoramic X-ray information of whole jaw tomographic planes, and includes multiple tomographic trajectory imaging means that classify a large number of dental and jaw region tomographic trajectories with different shapes for each patient. In addition, the dental arch detector measures the distance A between the left and right canines of the subject and the distance B from the straight line connecting both canines to the front edge of the central incisor. The radius of curvature R of the dental arch formed by each tooth is determined from the following equation (1), the shape of the individual fault trajectory is detected, and the trajectory shape detected from among the plurality of fault tracks is 1. A dental full-mouth X-ray imaging apparatus, characterized in that it is provided with trajectory selection means for selecting tomographic trajectories that match or are very similar. R=4B ² +A ² /8B ...(1) 2 Dental full-mouth X-ray photography according to claim 1 of the utility model registration claim, in which the dental arch detector measures measurement values A and B simultaneously. Device. 3. Scope of claims for utility model registration, Paragraph 1 or 2. The dental full-mouth X-ray imaging device according to item 2. 4 Trajectory selection means uses measured values A and B of the dental arch detector
2. A dental full-mouth X-ray imaging apparatus according to claim 1 or 2, which selects a trajectory of an output signal corresponding to the equation (1) by calculation of equation (1) or other signal processing.