JPS6116172B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a probe used in a device for measuring and diagnosing tooth movement.

Diagnosis of the degree of tooth movement is essential when diagnosing periodontal diseases.

Conventionally, the degree of tooth movement has generally been diagnosed by the operator using forceps or fingers to judge by the feeling when the tooth is moved in the buccolingual or mesio-distal direction; This has the disadvantage of not being able to make sufficiently accurate judgments due to the addition of subjectivity in addition to the individual's experience and individuality.

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, and the displacement of the teeth at that time was measured using a dental micro- Quantitative diagnosis methods were used by measuring with a meter or dental dial gauge, but
This method had many drawbacks, such as requiring the patient to be firmly fixed on a stable and only being able to diagnose the front teeth because the molars were taken as a reference, 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, we consider a tooth movement model in which the tooth contains viscosity and has no mass (mass of the tooth body) due to the spring, and the resonant frequency is inversely proportional to the degree of movement.In other words, as the degree of movement progresses, the resonance frequency increases. This method attempts to determine the degree of tooth movement based on the regularity of decrease.

However, this method involves fixing the patient's head, temporarily bonding a small acceleration sensor to the lingual side of the tooth, and applying vibration to the tooth using a dental hammer or an electromagnetic vibration drive device. This method determines the vibration frequency by detecting the vibration acceleration caused by vibration, and it is complicated because it is difficult to securely fix the patient's head, and it is necessary to temporarily attach an acceleration sensor to the tooth and remove it after each measurement. And it was 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 makes the work troublesome but also has disadvantages such as causing discomfort to the patient. Furthermore, since a DC servo motor is used to continuously apply stress, the device becomes large and has the disadvantage of causing pain to the patient over a long period of time.

In view of the above-mentioned conventional circumstances, the applicant used 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 further analyzed the frequency using a frequency analyzer. A tooth movement diagnostic device has been proposed whose main feature is to display the analyzed results on a display, but the purpose of this invention is to obtain a convenient and easy-to-handle probe for use in the device. That is.

As schematically shown in FIG. 1, this invention holds a probe equipped with a piezoelectric element P in a case 3 using an elastic material, and further includes a drive section for applying an impulse shock to the probe 1. The piezoelectric element converts the static pressure applied to the tooth through the probe 1 and the vibration generated in the tooth due to the impulse impact applied to the tooth into voltage, and further converts the static pressure applied to the tooth through the probe 1 into voltage. The main feature is that it also has the function of applying an impulse impact to the teeth via the .

The probe configured as described above is applied to a tooth movement diagnosing device having an outline as shown in FIG. Below, FIG. 1 will be briefly explained. The output of the piezoelectric element P of the probe 10 is input to the static pressure detection circuit 20, and the static pressure when the probe 1 is held in the hand and the tip of the probe 1 is pressed against the tooth A to be diagnosed is determined. When a certain value is reached, a confirmation signal _S1 is output.

The output of the static pressure detection circuit 20 is sent to the drive current generation circuit 3.
0, and furthermore, the drive current generation circuit 3
The output of 0 is input to the drive section 5 of the probe 10. When the static pressure detection circuit 20 transmits the confirmation signal _S1 , a drive current is outputted from the drive current generation circuit 30 to the drive section 5 of the probe, and an impulse shock is applied to the tooth A to be diagnosed via the probe 1. It is.

The output of the piezoelectric element P is on the other hand a frequency analyzer 40
The analyzer 40 also has a display 5.
0 is connected. Simultaneously with the generation of the confirmation signal _S1 , the frequency analyzer 40 enters the set state, and analyzes the frequency of the vibration generated in the tooth A by the impulse impact applied to the tooth A as described above, and displays it on the display 50. be. The diagnostician determines the degree of tooth movement based on whether the vibration frequency of the tooth displayed in this manner contains many high-frequency components or many low-frequency components.

FIG. 2, FIG. 3, and FIG. 4 show embodiments of the probe according to the present invention.

First, the present invention uses a probe 1 that plays a central role in achieving the above functions. Probe 1
The piezoelectric element P is sandwiched between the rod body 21 and the vibration tip 22 of the rod body 2, which has a vibration tip 22 attached to the tip thereof. Various methods can be considered for attaching the main body 21 of the rod 2, the piezoelectric element P, and the vibration chip 22, and to put it simply, the three may be bonded together with an adhesive. However, as a surefire way to make it more durable,
4 to 4 show a configuration in which a vibration tip 22 is screwed onto a rod main body 21. That is, the male screw of the vibration chip 22 is screwed into the female screw provided on the main body 21, and the piezoelectric element P, which has a hole large enough for the male screw of the vibration chip 22 to loosely pass through, is inserted between the two. It is included.

Further, FIG. 7 shows an embodiment in which a vibration tip 22 is screwed onto the rod main body 21 so as to cover it.

Since this probe 1 has a function as an acceleration sensor when detecting the vibration of the tooth, it needs to be as light as possible compared to the weight of the tooth in order to accurately extract the vibration of the oscillator, that is, the tooth. A light alloy such as aluminum or titanium is preferable, and in this embodiment, a cylindrical material having a diameter of 7 mm made of polyacetal resin, Diuracon, or Delrin is used. In particular, since it is sufficient for the vibration tip 22 at the tip to have the function of transmitting the above-mentioned impulses and tooth vibrations, it is necessary to reduce the weight as much as possible in terms of material and shape. Therefore, in the examples shown in FIGS. 2 to 4, the striking tip 2 has a tapered tip.
2 is used. In order to convert tooth vibration into voltage more efficiently, the characteristic impedance of the piezoelectric element P should be close to the characteristic impedance of the rod 2, and a piezoelectric element with a high piezoelectric index with respect to the force in the longitudinal direction of the rod 2 should be used. .

The probe 1 is supported by a case 3 using an elastic material 4. By doing so, the tooth vibrations will be efficiently transmitted to the rod body 21 of the probe 1. The elastic material 4 used here is preferably made of a material that is as light in weight as possible so as not to increase the effective mass of the probe 1. Furthermore, the compliance of the elastic material 4 used here is preferably selected to be as large as possible. That is, this is to prevent resonance with tooth vibration from occurring in this holding portion.

FIG. 3 shows a case where a spring spring is used as the elastic material. Another spring spring 4 is inserted between the front surface of the drive magnet 52 and the rear end of the probe 1 to obtain an appropriate pressing force against the tooth.

The probe 1 is configured so that an impulse impact can be applied to the tooth by a driving section 5. Basically, the configuration is such that electrical-mechanical conversion is performed by passing a drive current output from a drive current generation circuit through the drive coil 51, and various commonly used embodiments can be applied. can. Second
In the case shown in FIGS. 3 and 3, the electromagnetic force from the drive coil 51 is directly transmitted to the probe 1, and will be further explained below. A lightweight cylindrical member 2' is attached to the rear end of the probe 1, and a driving coil 51 is wound around the cylindrical member 2'.A driving magnet 52, which is loosely fitted into the cylindrical member 2', is mounted on the rear end wall of the case 3. It is installed. A magnetic tube 53 is further attached to the case side pole of the drive magnet 52 so that the magnetic field formed by the drive magnet 52 forms a strong parallel magnetic field M ₅ around the coil 51. When the drive unit 5 is configured in this way and an impulse current is passed through the drive coil 51 from the drive current generation circuit (see first reference),
An impulse impact is applied to the tooth via the probe 1 due to the repulsion or attraction of the strong parallel magnetic field _M5 .

In the embodiment shown in FIG. 4, the mechanical force generated by the electromagnetic force is temporarily stored in a spring spring 56 having a weighted ball 57 attached to the tip thereof, and the weighted ball 57 pushed out by the spring spring 56 moves the probe 1. It generates an impulse impact by colliding with the rear end, and has a plunger 55 with a weight ball 57 attached to the tip via a spring spring 56.
The probe 1 is supported on the case 3 using an elastic material 59 on the rear side. In this case, the weight ball 57 is positioned slightly behind the probe 1, and the weight ball 57 is arranged so that when it is pushed out by the spring spring, it collides accurately with the rear end of the probe. It is housed in a swinging tube 60 that fits loosely into it. The plunger 55 is an air-core drive coil 51 attached to the case 3.
It penetrates through the air core portion 51', and its diameter is made thicker at the rear than at the front of the air core portion 51'. Drive part 5
When constructed in this way and a driving current is applied to the driving coil 51 for a certain period of time, the operation shown in FIG. 5 is exhibited.

FIG. 5 shows the movement of the probe 1 and the drive unit 5 over time, where a is the probe and b is the probe.
is the drive part, and c is a graph of the movement of the plunger and weight ball of the drive part.

First, time t=t ₀ is an initial state in which there is no driving current output from the external driving current generating circuit 30. Next, the probe 1 is pushed against the tooth to be diagnosed with a constant pressure, and the static pressure detection circuit outputs a driving current according to the confirmation signal issued when the pressure reaches a constant value. This is the state shown at t= _t0 . At this time, the plunger is attracted to the drive coil 51 and stores energy in the spring spring 56. The energy accumulated in the spring 56 in this manner pushes the weight ball 58 forward and causes it to collide with the rear end of the probe 1 at t=t ₀ . At this time, the most effective method is to cause the collision just before the spring spring 56 is fully extended, and therefore it is necessary to adjust the distance between the weight ball 57 and the rear end of the probe 1 in advance. The fully extended spring spring 56 gradually contracts and returns to its initial position. When the drive current is cut off at time t= _t2, the plunger 55 also returns to its initial position, thus completing one process.

The drive section 5 shown in FIGS. 2 and 3 has the advantage of having a relatively small number of parts, but the drive coil 51 acts as an inductance with respect to the drive current, and the impulse current itself is instantaneous. However, the disadvantage is that the impact on the probe 1 is not very sudden. On the other hand, if the drive section is configured as shown in FIG. 4, the number of parts will increase somewhat, but it has the advantage of being able to apply a sudden shock to the probe 1.

6a, b, and c show various embodiments of the shape of the tip of the vibration tip 22 at the tip of the probe 1. FIG. When the percussion tip 22 has a tapered shape as shown in FIG. 2, the percussion tip 22 is pressed against the tooth A to be diagnosed from the buccal side for diagnosis.
If the tip is made into an L-shape as shown in Figure 3a,
A diagnosis of an impacted tooth can be made. If the tip is bifurcated as shown in Figure b, diagnosis can be made using pressure in both directions, pushing or pulling.Furthermore, if the tip is made into a hook shape as shown in Figure c, diagnosis can be made by pulling pressure. If these swing chips are used depending on the situation, effective diagnosis can be made.

However, when the drive unit 5 of the embodiment shown in FIG. 4 is used, it is not possible to use the vibration tip 22 having a hook-shaped tip as shown in FIG. 6c.

FIG. 8 is a model depicting, as an equivalent circuit, the state in which the present invention is pressed against a tooth to be diagnosed. Tooth A has mass M ₁ , compliance C ₁ and viscous resistance R ₁
The probe 1 is connected to the gums via the
M ₂ is the compliance of bar 20 C ₂ and elastic material 4
Compliance of C ₃ and is connected to Case 3.

What is important here is that the vibration caused by the impulse impact of the tooth is reduced to the resonance frequency of the interior of the probe 1 (mass M ₂ and compliance C ₂ ) or the probe 1 and case 3 (mass M ₂ and compliance C ₃ ). It is important not to absorb it.

Therefore, in this invention, the rod body 2 is made of as hard a material as possible, the resonant frequency of the probe 1 itself is set as high as possible than the resonant frequency band of the tooth (10 ² order), and the compliance of the elastic material 4 is _C3 is made as large as possible to keep the resonance frequency of the probe 1 and elastic material 4 as low as possible below the tooth resonance frequency band.

As explained above, this invention has the effect of objectively measuring the degree of tooth movement by simply holding the probe in the hand and pressing it against the tooth to be diagnosed by applying it to a tooth movement degree diagnosing device. ing.

Furthermore, as shown in FIGS. 2 and 3, when a drive coil and a drive magnet are used as the drive section, other uses are available as follows. In other words, the tooth impedance for the specific frequency is detected by pressing the probe of this probe against the tooth with a constant pressure, passing a current of a specific frequency through the drive coil, and measuring the electromotive force of the piezoelectric element. That's what I do. This impedance is also obtained as a standard for measuring the degree of tooth movement.

Furthermore, when a weighted ball pushed out by a spring coil is used as the drive unit, as shown in Figure 4, it is possible for the weighted ball to apply an extremely sudden impulse impact to the probe. can.

[Brief explanation of the drawing]

Fig. 1 shows a tooth movement degree diagnostic device to which this invention is applied, Figs. 2, 3, and 4 show an embodiment of the invention, and Fig. 5 shows a device using the embodiment shown in Fig. 4. An explanatory diagram of the operation in this case. Fig. 6 shows various embodiments of the percussion tip, Fig. 7 shows an embodiment of the probe, and Fig. 8 shows a model of the probe of this invention pressed against a tooth. be. In the figure, 1... Probe, 2... Rod body, 21... Rod body, 22... Vibration tip, 3... Case, 4
...Elastic material, 5...Drive unit, 56...Spring coil, 57...Mass sphere, A...Tooth, P...Piezoelectric element.

Claims (1)

[Claims] 1. Converting mechanical vibrations generated in teeth into electrical vibrations by applying an impulse impact to the teeth,
A probe used in a tooth movement diagnostic device that determines tooth movement by frequency analysis of the electrical vibration is composed of a rod body and a percussion tip attached to its tip. A probe having a piezoelectric element interposed between the rod main body and the vibration tip of the rod is held in the case using an elastic material with the tip protruding from the tip opening of the case, Further, a drive coil and a drive magnet are provided between the case and the probe, and the repulsion or attraction force of the magnetic field between the coil and the magnet due to the impulse current from the drive current generation circuit is applied to the probe. communicate directly to or
Alternatively, a drive unit is provided for applying an impulse shock to the probe by colliding a weighted ball with the rear end of the probe using electromagnetic force generated by a drive coil disposed in the case. A probe for a tooth movement diagnostic device featuring: 2. A probe for a tooth movement degree diagnosing device according to claim 1, which uses a tapered percussion tip. 3. A probe for a tooth movement degree diagnosing device according to claim 1, which uses a percussion tip with an L-shaped tip. 4. A probe for a tooth movement diagnostic device according to claim 1, which uses a percussion tip with a hook-shaped tip. 5. A probe for a tooth movement degree diagnosing device according to claim 1, which uses a percussion tip with a bifurcated tip.