JPS6057347B2 - Tooth mobility diagnostic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring and diagnosing the degree of tooth movement.

When examining periodontal diseases, etc., it is difficult to diagnose the degree of tooth movement.

Conventionally, the degree of tooth movement was generally diagnosed by the operator using tweezers or fingers to judge the tooth by the sensation of movement in the buccolingual or mesio-distal direction. has the disadvantage that it is not possible to make sufficiently accurate judgments due to the addition of subjectivity in addition to the experience and personality of the user.

In addition, during the research stage, the patient's head was firmly fixed on a rest table, and a pressure gauge was used to push or pull the teeth. Quantitative diagnosis methods were used by measuring with a meter or dental dial gauge, but the patient had to be firmly fixed on a pedestal, and the molars were taken as a reference. There were many deficiencies, such as the fact that only the front teeth could be diagnosed, so it was hardly ever popularized as a general method.

Furthermore, a method for measuring the resonant frequency of teeth, which is the direct background to this invention, was also used at the research stage.

In other words, considering a tooth movement model in which the tooth contains viscosity and its mass (mass of the tooth body) is connected by a spring, the regularity that this resonance frequency is inversely proportional to the degree of movement, that is, as the degree of movement progresses, This method attempts to determine the degree of tooth movement based on the regularity that the resonance frequency decreases. However, this method involves fixing the patient's head, temporarily bonding a small acceleration sensor to the lingual side of the tooth, and then applying vibration to the tooth using a dental hammer or an electromagnetic vibration drive device. There is a method of determining the vibration frequency by detecting the vibration acceleration caused by the tooth movement, but it is difficult to securely fix the patient's head, and it is necessary to temporarily bond the acceleration sensor to the tooth and remove it after each measurement. However, it was complicated and unsuitable for practical use.

Furthermore, Japanese Utility Model Publication No. 56-28985 discloses a tooth swing measurement device in which a tooth is held between a pair of clamping bodies and a sine wave stress is continuously applied to the clamping body from a drive unit via a transmission shaft. There is.

However, when using this device to measure tooth swing, it is necessary to hold irregularly shaped teeth with a clamping member, which not only is cumbersome to operate, but also has disadvantages such as causing discomfort to the patient. Furthermore, since a DC servo motor is used to continuously apply stress, the equipment becomes larger.
Another drawback was that it caused pain to the patient over a long period of time. SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, it is an object of the present invention to provide a device that easily and accurately measures the degree of tooth movement.

This invention uses a piezoelectric element to detect mechanical vibrations generated at the resonant frequency of the tooth due to an impulse impact applied to the tooth as an electric vibration, and then displays the result of frequency analysis on a display device using a frequency analyzer. This is the main feature, and will be explained in more detail below.

FIG. 1 is a block diagram showing the outline of the invention.

Reference numeral 10 denotes a probe, which includes a probe 11 having a piezoelectric element P interposed at the tip of a rod.

child. The probe 10 has a function in which the voltage element P converts the static pressure applied to the tooth via the probe 11 and the vibration pressure generated by the impulse applied to the tooth into voltage, and It has the function of applying impulses to the teeth via the child 11. The output of the probe 10 is transmitted to the static pressure detection circuit 2.
It is entered as 0.

As will be described later, the static pressure detection circuit 20 supplies a drive current to the drive current generation circuit 30 when the static pressure when the probe 10 is held in the hand and the tip of the probe 11 is pressed against the tooth exceeds a certain level. A command signal S1 for generating is output. The drive current generation circuit 30 receives the command signal S1 and outputs, for example, an impulse drive current to the probe 10.

However, the mode of the drive current is
4, and is not limited to the impulse current. The output of the probe 10 is also input to a frequency analyzer 40.

Via the probe 11 of the probe 10, a voltage corresponding to the vibration pressure generated on the tooth when an impulse impact is applied to the tooth is guided to a frequency analyzer for frequency analysis. An output corresponding to the intensity of each frequency component analyzed by the frequency analyzer 40 and divided into a plurality of bands is displayed on the display 50.

FIG. 2 shows one embodiment of the probe 10 described above. Probe 11
The vibration tip 11b can be screwed onto the tip of the rod body 11a, and the vibration tip 11b is connected to the tip of the rod body 11a.
A piezoelectric element p is sandwiched between the rear end and the rear end of the piezoelectric element p. In this case, the piezoelectric element p is provided with a hole in the center that is large enough for the male screw of the vibration tip 11b to loosely pass through. Furthermore, the characteristic impedance of the piezoelectric element p is set close to that of the rod, and a piezoelectric element having a high piezoelectric index with respect to the force in the longitudinal direction of the rod is used.
Since this probe 11 has a function as an acceleration sensor when detecting the swing of the tooth, it is necessary to reduce the mass as much as possible with respect to the object to be measured, that is, the tooth. A light alloy of the same type is preferable, and in this embodiment, a cylindrical material with a straight diameter 711a made of polyacetal resin, Diuracon, or Delrin is used.

In particular, the vibrating tip 11b at the tip has the function of transmitting the above-mentioned impulses and tooth vibrations, so it must be considered a rigid body at the measurement frequency in terms of material and shape, and at the same time it must be lightweight. In FIG. 2, a tapered hitting tip is used. The probe 11 is supported by a case 12 using an elastic material 13.

By doing so, the tooth vibrations will be efficiently transmitted to the main body 11a of the probe 11. As for the elastic material 13 used here, it is preferable to avoid increasing the number of lightweight materials as much as possible. The probe 11 is configured to be able to apply an impulse impact to the tooth by a drive unit 14.

The drive unit 14 winds a drive coil 14b around a lightweight cylindrical member 14a attached to the rear end of the probe 11.
A permanent magnet 1 attached to the rear end wall of the case 12 is located around b.
4c and the magnetic body 14d provide a strong driving magnetic field 14a. Therefore, when an impulse current is applied to the drive coil 14b from the external drive current generation circuit 30, the magnetic field 14e
An impulse impact is applied to the tooth via the probe 11 due to the repulsion or attraction force. FIG. 3 shows one embodiment of the static pressure detection circuit 20, drive current generation circuit 30, frequency analyzer 40, and display 50. The static pressure detection circuit 20 sequentially connects an amplifier 21, a rectifier circuit 22, and a comparator 23, and outputs a command signal S1 from the comparator 23 when the output of the piezoelectric element p of the probe 11 reaches a certain value. do.

In Figure 3, transistor q1 relay LYl, LY2,
The circuit constituted by the switches SW2 and SW3 has a relay function between the static pressure detection circuit 20 and the drive current generation circuit 30 or frequency analyzer 40 described above. The drive current generating circuit 30 is configured to discharge the charge of the charged capacitor through the coil 14b, or to generate an impulse current by switching the transistor Q1 according to the input rectangular wave as shown in FIG.

The drive current generation circuit 30 configured in this manner generates an impulse current to the probe 10 when the command signal S is discontinued from the static pressure detection circuit 20 and the switch SWl is closed by the operation of the relay LY2. It flows through the drive coil 14b. However, the drive unit 14 on the probe 10 side may be implemented in various ways other than those shown in the drawings, and the output of the drive current generation circuit 30 does not necessarily have to be an impulse current, but may be implemented in any manner suitable for the drive unit 14. It is sufficient to output the current in the selected mode. The frequency analyzer 40 uses FFT (
FastFOur'IerTransfOrmatiO
n) Any device can be used as long as it has the function of being able to decompose into frequency components, such as an analyzer or a heterodi-7 type selective amplifier.

In FIG. 3, the output of the amplifier 41 is passed through filters LPl, BPl to BP6 and HPl for each different band, and the output of each filter is passed through the rectifying circuits R1 to R and the integrating circuits 11 to 11.
The case of outputting via I is shown. In addition, each integrating circuit 1
1~! The operational amplifiers Q, ~Ql4 used for are provided with switches SW, ~SWl2 that short-circuit the input and output sides,
When the command signal S1 is generated by the relay LYl linked to the transistor Q5, the switches SW4 to SWl
2 is set to 0FF to function as an integrating circuit. As the display device 50, a device having a two-dimensional display function, such as a CRT display, a pen recorder, a dot printer, or an XY plotter, can be used.

FIG. 3 shows the case where an LED array 51 is used. The output of each frequency band of the analyzer 40 is a standard that increases sequentially▼
The signal is inputted to each LED and D making up the LED array via a comparator array 52 to which pressure is applied, and as a matter of course, the greater the output in that band, the greater the number of LEDs lit. The method of use and operation of the tooth movement degree diagnosing device configured as above will be explained.

First, the user holds the probe 10 in his hand and presses the percussion tip 11b at the tip of the probe 11 against the tooth A to be diagnosed.

When the pressing force at this time reaches a certain value (for example, 50 f), the static pressure detection circuit 20 is activated and outputs a command signal S1. Next, according to the command signal S1, the drive current generating circuit 30 causes an impulse current to flow through the drive coil 14b, and the probe 1
Give an impulse to 1. The command signal S1 also controls the frequency analyzer 40, so that it functions as a frequency analyzer, that is, switches SW4 to SWl2 are turned off, so the vibration waves generated in the tooth according to the degree of tooth movement due to the impulse impact are piezoelectric. The signal is electrically converted by the element P, analyzed by the frequency analyzer 40, and input to the display 50 for display. As mentioned above, if the degree of tooth movement increases, the tooth Since the vibration frequency becomes low, the degree of tooth movement can be determined by looking at the frequency distribution displayed as described above. Fourth
The figure shows the above situation using graphs. Figure 4a shows the impulse current, Figure 4b shows the tooth vibration waveform after the impulse impact, and Figure 4c shows the frequency distribution of the vibration wave. Further, FIG. d shows the display state of the display 50.

As explained above, the present invention provides a static pressure probe having a probe with a piezoelectric element interposed at the tip of a rod, and a static pressure probe that is relatively easy to design as an individual circuit and can be implemented in various ways. With a simple configuration consisting of a combination of a detection circuit, a drive current generation circuit, a frequency analyzer, and a display, it is now possible to measure the degree of tooth movement, which previously relied on the operator's experience and intuition, on the tooth being diagnosed. This has the effect of making it possible to perform the test objectively and accurately by simply pressing the tip of the probe lightly and reading the results displayed on the display.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the outline of the invention. Figure 2 is an example of a probe, Figure 3 is an example of a static pressure circuit impulse current generating circuit, a frequency analyzer and a display, and Figure 4 is an example of an impulse current, tooth vibration waveform and its frequency distribution, and an LED. Indicates the display state of the array. 10...
... Probe, 11... Probe, 11a... Rod body, 11b... Vibration tip, 12...
Case, 13...Elastic material, 20...Static pressure detection circuit, 30...Impulse current generation circuit, 40...Frequency analyzer, 50...・・・
・Indicator, P...Piezoelectric element.

Claims (1)

[Scope of Claims] 1. A rod has a probe with a piezoelectric element interposed at the tip thereof, and the electrostatic pressure applied to the tooth through the probe and the impulse impact applied to the tooth are A probe comprising a drive unit that converts vibrational pressure generated in the tooth into voltage and further applies an impulse impact to the tooth via the probe, and a static pressure detection circuit that detects the static pressure output of the probe. , a drive current generation circuit that outputs a drive current to the drive unit to give an impulse to the tooth when the output of the static pressure detection circuit exceeds a certain value, and a frequency analyzer that analyzes the frequency of the vibration pressure output of the probe. and a display device that displays the analysis results of the frequency analyzer. 2. A probe having a piezoelectric element interposed at the tip of a rod is held in the case using an elastic material with the tip protruding from the tip opening of the case, and an impulse is applied to the probe. Claim 1, comprising a drive unit for applying an impact.
The probe of the tooth movement degree diagnostic device described in 2. 3. Claim 1, which uses a probe in which the rod is composed of a rod body and a vibration tip attached to the tip thereof, and a piezoelectric element is sandwiched between the rod body and the vibration tip. Section, 2nd
The probe of the tooth movement degree diagnostic device described in 2.