JPH03173559A - Root pipe length measuring device and root pipe remedial device - Google Patents

Abstract

PURPOSE:To enhance the improvement in measuring sensitivity without causing pain to the patient by detecting the change of a peak voltage generated between a measuring electrode and a mouth electrode at the time of applying an impulse measuring signal between both the electrode, and measuring a root pipe length. CONSTITUTION:A rectangular wave pulse (a) is converted into a fixed impulse signal (b) having a fixed peak current value by a voltage converting part 5. Thus, the peak voltage of the terminal voltage of a primary coil 11a is proportional to the impedance between a measuring electrode 2 and a mouth electrode 3, and this voltage is detected by a signal detector 6 and peak-held by a peak hold circuit 7. The thus-obtained peak hold signal (d) becomes small with the impedance being lowered as the measuring electrode 2 is introduced into a root pipe more deeply, and on the other hand, the output signal (e) of an amplifier 8 becomes large. As the measuring signal has impulse form, and the impedance is detected by its peak voltage, the peak value can be increased to a value easy to detect while suppressing the average current value to about 5mum or less which never causes pain to a patient.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to improvements in a root canal length measuring device and a root canal treatment device used in root canal treatment in dentistry.

<Prior art> Currently used root canal length measuring devices pass an alternating current of around 4oμA between a measurement electrode and an oral electrode.
Many devices detect the root canal length from the impedance between both electrodes. However, it is generally difficult to accurately measure the root canal length because the measured impedance varies considerably depending on the conditions inside the root canal, such as whether it is dry or wet.

In order to solve this problem, a method has been proposed in which the influence of root canal resistance is removed by using currents with two different frequencies as measurement currents (for example, Japanese Patent Publication No. 62-2817). (see official bulletin). This takes advantage of the fact that the magnitude of the measured current varies depending on the frequency, and that the current increases rapidly near the root apex and the difference between the two becomes the smallest.

<Problem to be solved by the invention> However, in the above-mentioned publication, even when the tooth to be measured changes, the difference between the two types of measurement current is not kept constant until the current increases rapidly. This makes it difficult to handle as it requires adjustment each time a measurement is made, and the range in which the current increases rapidly is only around 1.5 mm, making it difficult to use because the measurable range is narrow. There's a problem.

Furthermore, not only the one in the above publication, but a current of around 40μ8 is likely to cause pain to the patient during measurement, and it is desired to further reduce the measurement current, but if the current is smaller than this, the sensitivity decreases. At the same time, it becomes susceptible to the influence of noise, leading to problems such as malfunctions and measurement errors.

In addition, this type of root canal length measurement device is affected by the noise generated by root canal treatment devices equipped with root canal treatment needles, such as file drillers, so it is not possible to use a resetting device at the same time.
It was inconvenient.

This invention focuses on these problems and provides a root canal length measuring device that can improve sensitivity without causing pain to patients and is easy to handle. The purpose of this invention is to provide a root canal treatment device that can perform both at the same time.

<Means for Solving the Problems> In order to achieve the above object, the root canal length measuring device of the present invention uses an impulse-like measurement signal, and the impulse-like measurement signal is connected between the measurement electrode and the oral cavity electrode. The root canal length is measured by detecting a change in the peak voltage that occurs between both electrodes while this measurement signal is being applied.

In addition, the above impulse-like measurement signal has a constant current waveform with a constant peak value, and when this measurement signal is supplied between the measurement electrode and the oral cavity electrode, the impedance between the two electrodes is determined by the peak voltage generated between the two electrodes. I'm trying to detect it.

The above-mentioned impulse-like measurement signal can be supplied to the measuring electrode and the oral cavity electrode via an isolation transformer or an autotransformer type transformer. A capacitor is connected in series between the electrode and the electrode which is not at ground potential.

Further, the root canal treatment device of the present invention is equipped with the root canal length measuring device described above, in which a root canal treatment needle such as a reamer or file also serves as a measurement electrode, and a measurement signal is supplied to the root canal treatment needle. There is. In this case, the measurement signal is preferably supplied to the root canal treatment needle via an isolation transformer.

Furthermore, this root canal treatment device has a function that automatically stops driving the root canal treatment needle or reduces the driving force when it is detected that the tip of the root canal treatment needle has reached the vicinity of the root apex. It is also possible to provide a notification function that emits sound, light, etc.

<Function> In the root canal length measuring device of the present invention, when the tip of the measurement electrode reaches the vicinity of the root apex, the impedance between it and the oral cavity electrode decreases rapidly. This is because the area near the root apex is filled with electrolyte solution, so a DC resistance bone is connected in parallel to the capacitor formed by these electrolytes between the measurement electrode and the oral electrode. An equivalent circuit is constructed in which a DC resistance is connected in series with this,
As the measurement electrode is inserted deeper into the root canal, the capacitance of the capacitor due to the electrolyte increases and the impedance becomes lower. Since the impulse-like measurement signal contains many high-frequency harmonics, the capacitor made of the above electrolyte exhibits a considerably large capacity near the apex, and its influence becomes very large, causing the impedance to suddenly increase. It is estimated that this will decrease.

This invention is an application of this principle, in which the measurement signal is in the form of an impulse and the impedance is detected by its peak voltage, so the average current value can be reduced to about 5 μA or less, which does not cause any pain to the patient. This makes it possible to raise the peak value to a value that is easy to detect while suppressing the amount of heat generated, thereby improving measurement sensitivity and making it possible to perform accurate measurements. In addition, as mentioned above, the capacitance of the electrolyte is the main factor that determines impedance, so an oxide film is formed on the surface of the measurement electrode, increasing the resistance, or a double layer is formed around the electrode, which increases the mobility of ions. There is little effect such as a decrease in current flow, and there is no need for fluctuations in measurement results or the need for adjustment each time a measurement is made.

In addition, as mentioned above, the root canal treatment device of the present invention has high sensitivity for root canal length measurement and is resistant to noise generated by other electrical equipment, so root canal length measurement and root canal treatment can be performed at the same time.
An automatic stop function prevents problems such as over-shaving.

Next, examples will be described.

<Example of root canal length measuring device> Fig. 1 is a block diagram, Fig. 2 is a circuit diagram of the first embodiment,
FIG. 3 is a signal waveform diagram.

In Fig. 1, 1 is the tooth whose root canal length is to be measured, 2 is a measurement electrode inserted into the root canal of tooth 1, and 3 is an oral electrode placed in contact with the surface of the soft tissue near tooth 1. be.

A indicates the root canal length measuring device, A□ indicates the impulse generating part,
A2 is an impulse supply section, A3 is a signal detection section, A4 is an amplification section, and A is a display section.

FIG. 2 is a schematic circuit diagram showing an example of a specific configuration.

4 is a rectangular wave generation circuit that generates a rectangular wave pulse (a); 5
is a voltage conversion unit that converts a rectangular wave pulse (a) into an impulse signal (b) and supplies it between the measurement electrode 2 and the oral cavity electrode 3; this voltage conversion unit 5 has a primary winding 1 that is insulated from each other
1a and a secondary winding 11b, and a high resistance 12 connected in series to the primary winding 11a.

The above rectangular wave pulse (a) is selected to have a peak value of 6 V and a frequency of 2 kHz, for example.

6 is a signal detector that detects and amplifies the terminal voltage of the primary winding 11a and outputs a signal (C), and 7 detects the positive or negative peak of the signal (C) and outputs a signal (d). 8 is an amplifier that inverts and amplifies the signal (d) and outputs an output signal (e), and 9 is a display section that operates according to the output signal (e). The amplifier 8 includes an offset adjustment resistor 13 that sets the output to 0 when not measuring. A gain adjustment resistor 14 is provided to adjust the output level, and the display section 9 is provided with an ammeter 15. In the figure, 16.1
7 is an inverter, and 18, 19, 20 and 21 are operational amplifiers.

Note that (a) to (e) in FIG. 3 show the waveforms of the above-mentioned signals (a) to (e), respectively. Since the impulse signal (b) does not generate a DC component, it is preferable to use an AC waveform as shown in the figure, but depending on the case, it is also possible to use a waveform with only one side, and the individual impulses of the impulse signal A damped vibration waveform as shown in FIG. 3(b') may also be used.

Next, the operation will be explained.

High resistance 12 of voltage converter 5 and primary winding 11 of transformer 11
a is 1 when the peak voltage of the square wave pulse (a) is 6V.
The impedance ratio is such that the terminal voltage of the next winding 11a is about 0.1V, and constitutes a kind of constant current waveform conversion circuit. The value is converted into a constant impulse signal (b). Therefore, the peak voltage value of the terminal voltage of the primary winding 11a is proportional to the impedance between the measurement electrode 2 and the oral cavity electrode 3, this voltage is detected by the signal detector 6, and the peak voltage value is detected by the peak hold circuit 7. will be held.

The peak hold signal (d) obtained in this way gradually becomes smaller as the measuring electrode 2 is inserted deeper into the root canal because the impedance becomes lower, and the output signal (e) of the amplifier 8 becomes larger.

According to impedance measurements using extracted teeth, when the tip of the measuring electrode reaches the vicinity of the root apex, the equivalent resistance value is approximately 2Ω, so 1. The gain adjustment resistor 14 of the amplifier 8 is adjusted so that the ammeter 15 shows a predetermined deflection when a resistor of Ω is connected to the This means that it is possible to detect when the apex has been reached. It is also possible to set the scale of the ammeter 15 to correspond to the insertion depth of the measuring electrode 2.
In this case, the insertion depth can be directly read from the deflection of the ammeter 15.

In this embodiment, an isolation transformer 11 is used in the voltage converter 5, so it is safe to use a commercial power source as a power source in this type of device in which the electrodes 2 and 3 come into direct contact with the human body, and it is safe to use a battery. It is possible to eliminate malfunctions caused by battery consumption, which occur in conventional devices used as power sources.

FIG. 4 shows a second embodiment, in which an autotransformer 25 is used in the voltage conversion section 5. In this example, the measuring electrode 2 is connected to the intermediate tap 25a, and a capacitor 26 is connected in series between the measuring electrode 2, which is not at ground potential, and the intermediate tap 25a. Therefore, the measurement electrode 2 is isolated from the power supply side in terms of direct current by the capacitor 26, and safety is improved when a commercial power supply is used as the power supply.

Note that the capacitor 26 may be inserted into the primary side of the autotransformer 25, and even when an isolation transformer is used, a capacitor can be used in combination to further improve safety.

In the embodiment shown in FIG. 2, in which an isolation transformer 11 is used in the voltage converter 5, the circuit of the measurement electrode 2 and the oral cavity electrode 3, which are the circuits on the patient side, is separated from other circuits in terms of direct current. Safety is particularly improved in this state, but combined with the high sensitivity, it also becomes possible to use it in conjunction with other electrical equipment.

Note that the rectangular wave generation circuit 4 and signal detector 6 shown in FIG.
, the peak hold circuit 7, the amplifier 8, etc. are merely examples, and each of these circuits can be configured as appropriate using well-known techniques.The impulse-like measurement signal is Instead of using the combination of 5, it may be possible to directly generate the signal using another suitable circuit. Furthermore, although an ammeter is used as the display section 9 in this embodiment, various other display means or notification means may be provided, such as emitting appropriate notification sound or light.

<Embodiment of Root Canal Treatment Apparatus> FIG. 5 is a block diagram showing an embodiment of the root canal treatment apparatus, and FIG. 6 is a diagram showing a schematic configuration of the apparatus of the same embodiment.

A' is a root canal length measuring section corresponding to the above-mentioned root canal length measuring device, which includes an impulse generating section A1 and an impulse supplying section A2.
, a control signal output section A6 is provided in addition to the signal detection section A3, the amplification section A4, the display section A1, etc.

B is a control section of the root canal treatment device, B section is a power setting section, B2 is a power control section, B is a power stop or reducer, C section is a drive section, and C2 is a reamer, file, etc. This is a root canal treatment device that also serves as a holder for a root canal treatment needle 2a. These devices have basically the same configuration as conventionally known devices.

The root canal treatment needle 2a also serves as a measurement electrode.

The power setting section B1 sets the cutting force (amplitude) of the root canal treatment needle 2a, and is operated by an adjustment knob (not shown) provided on the operation panel of the control section B, and the power control section B2 is set according to this setting. is adapted to drive the drive section C. This drive section C is an appropriate drive source such as a micro motor, air motor, or ultrasonic vibrator built into the handpiece, and is connected to the control section B through a main tube D1, and its mechanical output is It is transmitted to the root canal treatment needle 2a via the canal treatment device C2. Further, the power stop or reducer B is composed of a switch circuit such as a foot switch (not shown), and is configured to control the output of the power control section B2 on/off or to limit the output to reduce the output depending on the operation. .

The root canal length measurement section A' is connected to the control section B and the oral cavity electrode 3 by a connection cord D2, and the measurement signal is outputted via the isolation transformer of the impulse supply section A2, and from the control section B to the drive section C. is supplied to the root canal treatment needle 2a through the fifth
As shown by the broken line in the figure, the circuit of the oral cavity electrode 3 may also be configured through a control section B and a drive section C. Also, root canal length measurement part A'
When it is detected that the tip of the root canal treatment needle 2a has reached the vicinity of the root apex, a control signal S is output from the control signal output section A, and is input to the control section B via the control code D3. This control signal S is directly input to the power control unit B2 to stop the operation of the power control unit B2 or reduce the output, but as shown by the broken line, the control signal S causes the power to be stopped or reduced by the power reducer B, It is also possible to activate the

In addition, as shown by the broken line, there is a notification section A7 in the root canal length measurement section A'.
is provided, and uses the signal from the amplifying section A4 to emit sound, light, etc. to notify that the tip of the root canal treatment needle 2a has reached the vicinity of the root apex.This allows the operator to stop the power of the foot switch, etc. The power may be controlled by manually operating the reducer B.

As shown in FIG. 6, the root canal length measuring section A' and the control section B use a commercial power source E1 as a power source, and the control section B is supplied with air E2 and water E3.

This embodiment has the above-mentioned configuration, and the control unit B drives the drive unit C1 to operate the root canal treatment needle 2a to perform root canal treatment, and at the same time operates the root canal length measuring unit A'. An impulse-like measurement signal is applied to the root canal treatment needle 2a, and the root canal treatment needle 2a is also used as a measurement electrode. In other words, while measuring the root canal length, for example, root canal cutting using ultrasonic waves can be carried out at the same time. When detected by A', a control signal S is output and the drive section C stops operating.

Alternatively, the output decreases and the needle stops functioning as a therapeutic needle.

Therefore, troubles such as over-shaving due to continuous operation of the root canal treatment needle 2a are prevented, and it becomes easy to properly perform root canal treatment.

Even if root canal length measurement and root canal treatment are performed at the same time, since the root canal length measurement section A' is highly sensitive, it will not be affected by noise from the root canal treatment device, and accurate measurements can be made. Furthermore, by separating the circuit of the root canal treatment needle 2a and the oral cavity electrode 3 from other circuits using an insulating transformer, safety is improved when commercial power is used.

Although the root canal length measurement section A' and the control section B are shown separated in FIG. 6, one can be incorporated into the other to form an integrated device.

<Effects of the Invention> As is clear from the above embodiments, the root canal length measuring device of the present invention applies an impulse-like measurement signal between the measurement electrode and the oral cavity electrode, and detects the peak generated between the two electrodes. The root canal length is measured by detecting impedance using voltage.

Therefore, while keeping the average current value below a level that does not cause pain to the patient, it is possible to increase the peak value and improve measurement sensitivity. Since the results do not fluctuate and adjustments are not required each time a measurement is made, an easy-to-operate device is obtained.

In addition, if the impulse-like measurement signal described above is used as a constant current waveform with a constant peak value to detect the peak voltage between the two electrodes, the impedance between the two electrodes can be extracted as a voltage, making detection easier. The circuit configuration becomes simple.

Furthermore, if an isolation transformer is used in the voltage conversion circuit or an autotransformer is used and a capacitor is connected in series between the secondary winding and an electrode that is not at ground potential, the electrode circuit can be connected to the DC voltage from the power supply side. It can be separated to improve safety, and commercial power can be used as a power source.

In addition, the root canal treatment device of the present invention takes advantage of the feature that there is no possibility of malfunction even when the root canal length measuring device is used in conjunction with other electrical equipment, and can perform root canal length measurement and root canal treatment at the same time. It is possible to obtain a device that is convenient and has an automatic stop function and a notification function, and prevents over-shaving, etc., and it is possible to obtain a device that is highly functional and easy to use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a root canal length measuring device according to the present invention;
FIG. 2 is a circuit diagram of the first embodiment, FIG. 3 is a signal waveform diagram of the same embodiment, and FIG. 4 is a circuit diagram of main parts of the second embodiment. FIG. 5 is a block diagram of an embodiment of the root canal treatment device according to the present invention, and FIG. 6 is a schematic configuration diagram of the device of the same embodiment. DESCRIPTION OF SYMBOLS 1... Tooth, 2... Measuring electrode, 2a... Root canal treatment needle, 3... Oral electrode, 11... Insulating transformer, 15...
- Ammeter, 25... Auto transformer, 26... Capacitor, A... Root canal length measuring device, A'... Root canal length measuring section, 80... Impulse generating section, A2... - Impulse supply section, A3... Signal detection section, A,... Display section, A6... Control signal output section, A7... Notification section, B.
...Control unit, B2...Power control unit, B...Power stop or reducer, C...Drive unit, S...Control signal.

Claims (9)

[Claims] (1) A root canal length measurement device that measures root canal length by detecting changes in impedance between a measurement electrode and an oral cavity electrode, and applies an impulse-like measurement signal between the measurement electrode and the oral cavity electrode. A root canal length measuring device characterized in that the root canal length is measured by detecting a change in the peak voltage generated between the two electrodes when this measurement signal is applied. (2) The method according to claim 1, wherein the impulse-like measurement signal is a constant current waveform with a constant peak value, and the impedance between the measurement electrode and the oral cavity electrode is detected by the peak voltage generated between the two electrodes. Pipe length measuring device. (3) The root canal length measuring device according to claim 1 or 2, wherein the impulse-like measurement signal is supplied to the measurement electrode and the oral cavity electrode via a transformer. (4) The root canal length measuring device according to claim 3, wherein the transformer is an insulating transformer in which the primary winding and the secondary winding are insulated. (5) The root canal length measuring device according to claim 3, wherein the transformer is an autotransformer, and a capacitor is connected in series between the secondary winding and a measuring electrode or an electrode that is not at ground potential of the oral cavity electrode. (6) A root canal treatment device comprising the root canal length measuring device according to claim 1, wherein the root canal treatment needle also serves as a measurement electrode. (7) The root canal treatment apparatus according to claim 6, wherein the impulse-like measurement signal is supplied to the root canal treatment needle via an insulating transformer. (8) When it is detected that the tip of the root canal treatment needle, which also serves as a measurement electrode, has reached the vicinity of the root apex, the drive of the root canal treatment needle is automatically stopped or the driving force is reduced. Claim 6
or the root canal treatment device described in 7. (9) When it is detected that the tip of the root canal treatment needle, which also serves as a measurement electrode, has reached the vicinity of the root apex, a notification is provided by a notification means that emits sound, light, etc. root canal treatment device.