JPS6122842A - Dental jaw x-ray photographing apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Fields This invention is used for dental treatment to take panoramic tomographic images of the facial region, including the oral cavity function and the upper and lower jaws, rather than just the dental structure. In particular, the present invention relates to a dental full-mouth X-ray imaging device that can obtain images close to actual size and with excellent sharpness by shortening and making the distance between the subject and the image receiving surface substantially uniform.

(2) Prior art The conventional dental full-mouth X-ray imaging device (referred to as a panoramic device) is a dental full-mouth X-ray imaging device (referred to as a panoramic device) that uses a single cassette holder with a constant relative distance between the The horizontal arm is vertically installed at both ends of the arm.The horizontal arm is suspended from a rotating mechanism such as an inner wall or a pseudo elliptical orbit system or a three-arc compound orbit system to move along the dental arch of the subject. When rotated, the image layer or tomographic area is limited to a pseudo-elliptical continuous curve of the dental arch.The temporomandibular joint is hardly included, and the temporomandibular joint becomes a sharp image equivalent to the dental arch. Difficult to photograph.

For this reason, conventional panoramic devices set the cassette holder's cassette feed speed IW faster than the rotational speed of the horizontal arm in the temporomandibular joint region, and at a speed synchronized with the arm rotation speed in the dental arch region. It is customary to perform so-called variable cassette feed linkage control to make the dental arch and one joint part a continuous fault area. The cassette feed rate variable control means may include, for example, a cam plate having protrusions formed in a shape similar to the series of fault areas, and a variable speed control means that corresponds to the rotational phase of the horizontal arm via a friction transmission mechanism. Mechanical interlocking systems are often used, such as one that controls cassette feeding. In addition, in recent years, the cassette holder has been equipped with a drive motor exclusively for feeding the cassette.
Various motor-driven devices have been devised to control the cassette feed with a variable speed that corresponds to the rotational phase of the horizontal arm, and compared to the mechanical interlocking type mentioned above, the mechanism is simpler and its variable controllability is superior. It is on the verge of becoming widespread. However, panoramic devices equipped with either mechanically interlocked or motor-driven cassette feed variable control mechanisms can simultaneously take tomographic images of the dental arches and temporomandibular joints;
Panoramic photographs have a major drawback in that the magnification ratio varies by 15 to 2 (1%) depending on the part of the subject. Figure 1 is a schematic diagram to explain this.Horizontal The arm (1) is rotated by, for example, a single-axis continuous movement rotation mechanism (2), and the cassette (4) of the cylindrical cassette holder (3) is rotated (by the mechanical or motor type cassette feeding control described above). arrow (5)
The feed speed in the direction is variable.

Note that the focal point (7) of the X-ray tube (6) and the cassette (41 (X
(synonymous with line film) is usually 5.
In order from 20 to 550, in this example, there are 530 doors and 1.

This configuration allows the horizontal Arno (11 suspension axes (8)
The floating Mm wheel (9), which is integral with the fixed sun gear u1)), is inscribed in the fixed sun gear u1).

While rotating in the direction of arrow (11), arrow a2 direction U! By rotating to
In the rotation wJ process of 4h), when the cassette (41id) rotates along the pseudo-elliptical trajectory shown by the two-dot chain line (161), the above 5
While the focal point-cassette distance (La) of 3Q*i remains unchanged, the distance (Lc) between the subject at the right temporomandibular joint end (5T) and the cassette (4) is, for example, about 30π! The minimum value of (Lc+3 increases with rotation, right second molar fl
? The maximum value (Lcz) is approximately 1101111. This (LC2) does not change during the dental arch trajectory (141), begins to decrease again after the left second molar (171), and returns to the above minimum value (Lc+) at the left 1st joint end <15T' In other words, in the snout joint tomographic area 05105!, even though the rotation range is narrow, the magnification of the subject changes continuously by 1.o 6: 1.26, about 2096 as in this example, making it a special image. Next door.

The sharpness also varies depending on the site, and there is a drawback that only images with extremely low diagnostic accuracy can be obtained. Furthermore, in the dental arch, the expansion rate does not change, but as shown in Figure 1, the temporomandibular joint trajectory (
15+ (Since +4 is spreading from side to side, even if you bring it as close as possible to this, the rotation trajectory of cassette (4) 06 (is fixed) 1, so it will be far away from the tooth row (La2) or about 10 cIn above. This is considered to be one of the factors that impairs the improvement of the sharpness and resolution of the dental arch image in the conventional apparatus, particularly in the anterior part region.

(3) Purpose The purpose of the present invention is to shorten the distance between the cassette and the subject as much as possible, and to reduce the distance between the cassette and the subject, in order to solve the problems and drawbacks of the conventional panoramic device mentioned above. ”! Equalize 2.
#Subjects throughout the entire fault trajectory! Panoramic photography is performed at a constant magnification rate.

To provide a dental residual X-ray device capable of obtaining sharp images close to actual size and having excellent resolution.

(4) Configuration Next, the gist of the configuration of this invention will be described.

The apparatus according to the present invention is no different from the conventional panoramic apparatus in terms of tomography principles and basic configuration.

The first major difference is the structure that allows the relative position of the cassette holder, which is hung vertically on the horizontal arm, and the horizontal arm suspension shaft to be movable. That is, in the case of an apparatus having a mechanically interlocked variable cassette feeding mechanism, the cassette holder hanging side arm is extended and contracted together with the transmission part of the mechanism provided on the horizontal arm. Further, in the case of an apparatus having a motor-driven variable cassette feeding mechanism, the cassette holder is moved independently, or the arm end portion of which the cassette holder is coated with silver is extended and retracted. The second point of difference is that the cassette of the cassette holder is brought close to the head and facial features, and the cassette is moved along a trajectory that corresponds to the rotational phase of the horizontal arm, that is, each part of the facial features, and approximately approximates the facial plane. For example, a cam that rotates.

This configuration uses a motor to control the relative position of the cassette holder and the horizontal arm suspension shaft.

(5) Examples The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a side (partial) view of the horizontal arm rotating section of a panoramic apparatus according to the first embodiment of the present invention, in which variable cassette feed control is mechanically interlocked. The pedestal (□□□), which has a built-in arm rotation mechanism (2) and is attached to a device (not shown) so as to be able to rise and fall freely, has the fixed sun gear Qtli (see Figure 1) of the rotation mechanism (2) and the A revolution mechanism CI'11 is provided in which the planetary gear (9) revolves around the center of the sun gear 00) while maintaining inscription therein. When the rotation motor ■ rotates, the rotation mechanism (2) is regulated by the revolution mechanism (21) and rotates on the gantry board □□□ via the rotating wheel 9) The suspension shaft (8) of the one-piece horizontal arm (1) is rotated, for example, by 220 degrees, as shown in FIG. Fixedly installed on the lower surface of the substrate (2) are a cassette drive mechanism, that is, a variable cassette feed speed control mechanism, and a cassette rotation control cam plate (a), which is one of the essential parts of this invention. The drive mechanism, that is, the mechanically interlocking speed controller S■ mentioned above will be briefly explained. Viewed from below, the △-shaped projection n formed on the cam (25) is approximately similar to the #l jaw fault trajectory of a51Q41 a4 shown in Fig. 1, and the friction cylindrical body ( The central axis of the support (1) is supported by a bearing (2) of a bearing stand fixed on the horizontal arm (1), and a small-diameter friction ring cil+ is fixed to the other end. Furthermore, the friction ring l31) is attached to the cassette holder (3).
It is in contact with a large-diameter friction roller c12 that is directly connected to the cassette rotating shaft. This configuration corresponds to the rotational phase of the horizontal arm (1), for example, in the dental arch area, the cassette feeding speed is synchronized with the arm rotational speed, and in the W joint area, the cassette feeding speed is increased. Variable control is performed. Next, the latter, that is, the cassette rotation control mechanism ω) using the cam plate will be described. First, to make the horizontal arm (1) extendable and retractable, separate the horizontal arm (1) into the cassette holder hanging side arm 134) and the hanging shaft and X-ray source hanging side arm 5). Each is formed into a rectangular tube shape, for example, and the movable arm 4) is inserted into the fixed arm 1. The fixed arm O) is configured to easily and slidably support and hang a movable arm 04), which is a cantilevered arm that receives concentrated loads at its free end. For example, in order to reduce the coefficient of friction between the two, the ball is generally placed at two locations, one at the end of the fixed arm and the other at a predetermined distance from the end.

A bearing (called a bush) is provided in which a number of balls roll along the axial movement of the shaft it supports and circulate through a cage. The end (9) of the movable arm is equipped with several spring stops (3Pl).

Several tension helical springs C39) having an appropriate spring constant are provided between the same spring stopper d on the fixed arm 05) side. The upper surface of the movable arm 341 is the cylindrical body (
A pillar (40) is slidably installed, for example by a construction method such as welding, slightly out of phase with (c), and the wheel (41) is rotatably supported on this pillar. This roller (41) is pressed against the above-mentioned cassette rotation control cam plate (5) by the elastic force of the tension spring G9).
It forms a shaped protrusion (A) and its side surface is made into a cam plate in the shape of a nendou. Here, the cassette rotation control cam plate (5) will be explained with reference to FIG. Figure 3 is a plan view of the human skull from above, showing in particular the relationship between the temporomandibular joint of the lower jaw and the #I bone, with other parts omitted. The dotted lines on the outer periphery of the spine (03), mandible (03) and skull (4) are the skin (45;
C45T) shows nasal convexity. Due to the revolution of the planetary gear (9) shown in Fig. 1, the gear shaft and the horizontal arm suspension shaft (8), which is a single unit, revolve while rotating in the direction of arrow 02. For example, the cassette holder (3) fixed at the end moves along the pseudo-elliptical trajectory 0 in the direction of the arrow (C+).
6) Rotate. For example, divide this rotation into 20 parts, (
3-0)・～(3-20). As explained in Fig. 2, the cassette holder (31,': horizontal arm suspension shaft (
This is because the relative position with the 8th ring can be changed.

As shown in FIG. 2, the distance (Lb) between the film (Fl) in the cassette and the axis (8C) can be variably controlled in any manner corresponding to the rotational phase by the shape of the cam plate. For example, the facial features shown in Figure 3P are close to each other, and the locus (4G
) When the cassette holder (3) is rotated along For example, if we take the phase (,3-0), the arrow (d) of the movable arm (5) (this direction is the phase (F
ls) After that, if the moving claw (in the opposite direction (el) is adjusted to zero in advance, the maximum movement amount of the movable arm r341 ((im
ax ) is several hundred, and the mechanism e described above allows for smooth operation. On the other hand, the facial appearance approximation trajectory (46) is 0 at the temporomandibular joint.
It is essentially parallel to the tomographic trajectory of the 510 eruption and the dental arch (141), and the magnification of the tomographic image is approximately 11% on average.

In addition, the variation in the magnification rate for each part is within 5% at most. Next, as shown in FIGS. 4 to 7, the second embodiment of the present invention, that is, the cassette drive is changed to the above-mentioned motor drive system, and the cassette rotation control means is an electric type (47
The panoramic device set to 1 will be explained. FIG. 4 is a side view of the photographing section of the above apparatus, and the mount (@) is the same as shown in FIG.

It has a built-in rotation mechanism (2) and is supported by a main pillar (not shown) so that it can be raised and lowered. The suspension shaft (8) of the rotation mechanism (2) suspends the fixed arm (18) on the side of the horizontal arm (1) on which the X-ray source (6) is suspended, and the fixed arm 1B+ is, for example, a flat cassette holder. (Movable arm 0 on each side with 35 hanging)
0 head positioning machine that supports 91 in an extendable manner @ (48
1 is fixed to the above-mentioned frame (3) via a support (49).

The subject's head, indicated by the chain dotted line group, is fixed in a fixed position. For example, a pulse motor (521) dedicated to feeding the sumo wrestlers is installed inside the cassette holder (3). This is a motor-driven cassette drive mechanism (51).

Therefore, there is no need to provide a cassette drive mechanism on the movable arm 091.FIG. is very close to his facial features. Not indicated by the dashed line 09nJli)
The ω position of 1 arm U9) indicates the sumo wrestler's note holder position corresponding to the left and right temporomandibular joints. Therefore, (QrrInx- is the maximum movement distance of the aforementioned movable arm 091+7). FIG. 5 is a partially cutaway plan view of the top cover of the pedestal 1 shown in FIG. 2) is a friction rotary body (with a diameter of about 200 mm), which is mounted on the rotating shaft of the friction rotary body (2).
54). As this rotating body (54) rotates approximately 2.2 times, the arm suspension shaft (8) rotates to (81) via a transmission mechanism (not shown), and the rotation angle ←
For example, it revolves around 220 degrees. A link plate (55) having, for example, one pitch of unevenness (the unevenness is shown as a part of the figure for simplicity) is provided over the entire circumference of the medium diameter rotating body Liu 1, and pulses are transferred by an optical encoder (A). If output, the rotation phase of the horizontal arm (1) will be 0 per barrel,
] Can be detected with high accuracy of 7°. This is the Arno rotation phase detection means detailed in the specification of Utility Application No. 1983-009828, "Arm rotation device for X-ray panoramic device for dental implants 1," which the authors previously proposed and filed. , in this invention, is a part (47A) of the cassette rotation control means (471) applied to the cassette holder rotation control using the detection signal of 0.17°/parnu.Next, moving to FIG. 6, FIG. This is a partially cutaway plan view of the upper cover of the horizontal arm (1) in FIG. 4, and shows the configuration of the next part (47R) of the cassette rotation control means that controls the position of the cassette holder (31) based on the above detection signal. This shows the M hanging shaft (8).
The fixed arm 081 and movable arm 091 that are integrated are 1
They are telescopically engaged by a pair of guide shafts. These guide shafts (G) are supported by the same pair of fixed stands (59) provided at movable A~/ (19j), and are supported by bearing stands ([a (611), two bearings each) on the fixed arm 08) side. Furthermore, an arm telescoping drive reversible motor, which is a pulse motor, for example, is fixed to a motor and support stand f6Z placed on a shelf on the fixed arm aa side, and its drive shaft fi41Vi is Motor support stand (6
It is supported by the bearing in 2) and the bearing in the bearing stand (G), and a threaded rod (Z) integrally connects it to the tip. A cylindrical nut member (63) screwed onto this threaded rod (6η) is fixed to the 9J moving arm 01)1. - In the configuration described in F, the movable arm (1) is assumed to rotate reversibly at a rotation speed corresponding to the above-mentioned arm rotation phase detection signal.
9) moves a fixed amount of each 19 in the direction of the arrow (1゛). In Figure 6, the point J is chained (1), when π moves a large amount (/]
The location of each part is shown. Figure 7 is the episode of Figure 5 above! l
! This is a block diagram of the digital control circuit (the remaining part (47C) of the above-mentioned cassette rotation control means (47I)) of the cassette holder position W (control means) shown in Fig. 11 phase detection means and the cassette holder position W shown in Fig. (Since the 5411d pulse motor rotates at a constant speed, the encoder fE13
The output signal No. 1 is a Varne signal (Sl) with a constant pulse interval. This signal (S+) is used for arm phase detection 1. i circuit 60
), and the same signal is input to the aforementioned cassette feed speed side control circuit group σj), but a description of this ff11 and its drive motor ff2) will be omitted since they are not directly related to this invention. The 67-phase detection circuit q■ continuously detects the arm rotation phase in units of 0.17° by counting the number of pulses (Sl) with a pulse counter, for example, and outputs the absolute rotational signal (Sl) as follows. 1
Cassette trajectory memo as 0-bit digital signal −
IJ ff3). This signal (Sl) is also the above (
Sl) Similarly, it is also input to ff1l. The facial appearance approximation trajectory (4 (G)) shown in Fig. 3 is already stored in the cassette trajectory memory at every 0.17° arm phase, and the final address is specified by (Sl) above, and the trajectory data (Sg) is output. This signal (Sl) is converted into a cassette holder movement amount signal (S4) by the cassette holder rotation control circuit, and is manually inputted to the pulse motor drive circuit a9 to generate the pulse signal shown in FIG. Drive the motor to move the film receiving surface in the cassette (4) along the above trajectory f461 (#
Figure 3: Volume and weight (1U).

The above are the first, third and second embodiments of this invention.

It goes without saying that the present invention is not limited to what is illustrated or described. For example, the cassette holder of the mechanically interlocking device shown in FIG. 2 may be flat, or the cassette holder of the motor-driven device shown in FIG. 4 may be cylindrical. Furthermore, the rotation mechanism may be of any type other than a continuous shaft movement type. Further, the facial appearance approximation locus (46) in FIG. 3 is not limited to what is shown in the figure, and various loci can be considered. The structure in which only the set holder is movable with respect to the arm and the above-described arm movable mechanism as well as the structure other than those in FIGS. 2 and 6 belong to the scope of the present invention. Not only panoramic equipment.

The present invention is also applicable to a panoramic device equipped with a cephalogram.

(6) Effect This invention is structured like a beam.

The distance between the subject of the tomographic trajectory photographed by the panoramic device and the film image-receiving surface can be shortened and made uniform as much as possible according to the facial features, and the distance can be approximately 1.0 mm over the entire teeth and jaws.
By keeping the 5th low magnification almost constant, images of the anterior tooth area, which has been a problem in the past, are close to actual size.
This provides a convenient device that can easily provide image quality with excellent sharpness and resolution and has high N3 diagnosis accuracy.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the variation in magnification of a conventional panoramic device, and FIG. 2 is a side (partial) view of the horizontal arm rotating part showing the configuration of the first embodiment device d of the present invention. Fig. 3 is a reading plan view showing the principle that the cassette of the device of this invention rotates on an approximate reading locus, Fig. 4 is a side view of the photographing section of the second embodiment of the device of this invention, and Fig. 5 is the above-mentioned device. FIG. 6 is a plan view showing the extension/contraction mechanism of the horizontal arm of the above device, and FIG. 7 is a digital control circuit as a cassette rotation control means of the above device. FIG.

Claims (1)

[Scope of Claims] 1. A horizontal arm with an X-ray source at one end and a cassette holder placed vertically at the other end across the subject's head; It is equipped with an arm rotation mechanism that rotates the circumference of the arm, and a cassette drive mechanism that moves the cassette of the cassette holder in the opposite direction of the arm rotation in accordance with the fault trajectory, so that the entire area of the teeth and jaws of the head can be viewed in a panoramic manner. In the apparatus for photographing, the cassette holder and the cassette drive mechanism are integrated into one unit, and the relative position of the horizontal arm with respect to the suspension shaft can be moved. Corresponding to the rotational phase of
A dental full-jaw X characterized by being provided with a cassette rotation control means for rotating the cassette along a trajectory that approximates the facial plane.
Ray imaging device. 2. The dental full-mouth X-ray imaging apparatus according to claim 1, wherein the cassette rotation control means is a mechanical means using a cam. 3. The dental clinic according to claim 1, wherein the cassette rotation control means comprises horizontal arm rotation phase detection means, and means for controlling the position of the cassette holder via a motor based on this detection signal. Full jaw X-ray imaging device.