JPS6225381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a dental diagnostic device for measuring root canal length, diagnosing pulpitis, or diagnosing the presence or absence of residual pulp in dentistry. The present invention relates to a dental diagnostic device.

A diagnostic device for measuring the root canal length of a patient's tooth, diagnosing the presence or absence of residual pulp, or diagnosing pulpitis during dental treatment has already been proposed and patented by the same applicant as the present application. has been done. For example, Japanese Patent Publication No. 52-23507 discloses in detail an embodiment of such an apparatus and its diagnostic method.

In the above-mentioned well-known device, when measuring the root canal length of a patient's tooth,
Adjust the knob of the variable resistor for adjusting the output current provided on one output terminal side of the DC-AC converter, and set it in advance so that the deflection of the measurement meter reaches a predetermined value. I was trying to prepare. That is, the positive type of the diagnostic device is connected to a probe such as a reamer, and its cathode is connected to an oral conductor such as a saliva ejector to form a closed circuit through the patient's living body, and the patient's body is detected by the reamer. When the pulp chamber is expanded and excavated into the tooth, a current approximately equal to the current flowing through the resistance of the living body between the two poles when the probe reaches the root apex of the tooth is displayed on the meter. The variable resistor for adjusting the output current was adjusted in advance so that the output current was adjusted.

However, since the above-mentioned diagnostic device uses a battery as a DC power source, depending on the frequency of use, the battery may be consumed to a considerable extent without realizing it, and the resulting voltage drop will cause a large error in measurement. Indeed, by adjusting the variable resistor for adjusting the output current every time a measurement is made, the deflection of the meter is checked in advance to prevent errors due to the voltage drop.

However, even if errors can be prevented to some extent by adjusting the output current with the knob of the variable resistor, there are individual differences in the adjustment depending on the user. Furthermore, the position of the knob may change by mistake during use, which can cause errors, and since measurements are made by passing current through the living body, in some cases the current may be excessive and may cause discomfort to the patient. It may even give you a sense of pleasure.

In addition, in the above-mentioned well-known device, no special measures were taken against the voltage drop of the battery as a DC power source, so normal measurement function was not always guaranteed as it changed over time. Furthermore, the output current adjustment operation for each measurement was also troublesome.

The present invention solves the above problems in view of the problems described above.In the present invention, a constant voltage circuit is provided for the DC power supply to guarantee measurement accuracy until a predetermined voltage drop is reached, and an operational amplifier (op-amp )
The circuit is simplified by providing an oscillation circuit that utilizes the At the same time, it is an object of the present invention to provide a dental diagnostic device that can guarantee stable measurement accuracy over a long period of time.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the configuration of a diagnostic device according to the present invention.
In the figure, 1 is a positive DC power supply (battery), 2 is a negative DC power supply, 3 is a stabilizing Zener diode for the positive power supply, 4 is a stabilizing Zener diode for the negative power supply, and 5 is the first This operational amplifier is connected to a non-inverting input via a positive feedback circuit with a resistor _R1 , a capacitor _C1 , a resistor _R2 , and a capacitor _C2 , forming a Wien Bridge type resonant circuit. Also, resistors R ₃ , R ₄ , R ₅ are bias resistors, R ₆
indicates the offset voltage adjustment resistor.

The output of the operational amplifier 5 is connected to the next stage via resistors R ₇ and R ₈ and a capacitor C ₃ . Reference numeral 6 denotes a second operational amplifier, and its inverting input side is supplied with a divided voltage via a switch S ₃ , a fixed adjustment resistor R ₉ , and a voltage dividing resistor R ₁₀ . The non-inverting input is connected to ground. Note that _R11 is an offset voltage adjustment resistor. 7 is a rectifier, and 8 is a meter for displaying the output current, the appearance of which is as shown in FIG. Switch _S5 is an R test switch that is pressed when diagnosing residual pulp, etc. It is linked with switch _S4 , and when it is pressed (on) A relatively large current is applied directly to the remaining marrow of the living body from the power source.

The input/output terminal 9 is a terminal that applies current to the patient's living body, and a cord 11 extends toward the patient via a connector 10, and its anode side is connected via a root canal conductor 22, as shown in FIG. The probe is connected to a probe 20 such as a reamer, and its cathode side is connected to a living body via a clip 23 and an oral conductor 21 to form a closed circuit. In addition, switches S ₁ and S ₂
indicates the power switch.

Note that the reference numbers shown in each part of the dental diagnostic apparatus according to the present invention shown in FIG. 2 correspond to those given the same reference numbers as the constituent elements of the apparatus shown in FIG.

FIG. 3 is a longitudinal cross-sectional side view of a tooth of a patient to be diagnosed using the diagnostic device of the present invention, and also shows the probe 20 connected to the anode of the device. The cathode side is connected to an oral cavity guide 21 such as a saliva ejector, as shown in FIG. 2, so that a closed circuit is formed within the oral cavity.

Next, the operation of the apparatus of the present invention will be explained. First, when the power switches S ₁ and S ₂ are closed, the device enters the operating state, and a stabilized voltage is applied to each part via the Zener diodes 2 and 3.

The operational amplifier 5 has a resistor R ₁ and _a capacitor C 1 connected between the non-inverting input and the output, and a resistor R ₂ and a capacitor C ₂ connected between the non-inverting input and the ground.
An oscillation output having a frequency determined by the value of and a predetermined amplitude is generated on the output side. The output is given to the input/output terminal 9 via switch S ₃ and switch S ₄ , from there via the cord 11, one pole is given to the probe reamer 20 via the root canal guide 22, and the other pole is given to the probe reamer 20 via the root canal guide 22. The poles will be applied to the oral conductor 21 via clips 23 or the like. The current flowing out from the input/output terminal 9 through the bioresistance that changes due to tooth excavation with a reamer or the like is applied to the inverting side input of the second operational amplifier 6 via the switch _S5 , so that it is amplified and its The output is rectified by a rectifier 7 and given to a meter 8 for measuring root canal length.
The meter 8 is designed to fluctuate depending on the condition of the teeth and the living body.

The present invention is configured as described above, and as an example, when measuring the length of the root canal 31 of a patient's tooth 30, first, the switch _S3 is pressed and the meter 8 is set to a predetermined value with respect to the current that should flow through the living body. Check the reference value. That is, in the present invention, since the values of the circuit components, that is, the resistors, capacitors, etc., are appropriately selected, when the switch _S3 is turned on to the B contact, the probe ₂₀ is connected through the fixed resistors _R9 and R10. When the tip of the meter 8 reaches near the root apex 32 of the tooth, the deflection of the meter 8 is automatically set to a maximum scale of 40. That is, since the basic resistance of the human body is approximately 6 kΩ, the fluctuation of the reference current flowing through the human body is adjusted to the fluctuation of the meter, for example, on a scale of 40.

Therefore, the resistance of the living body changes depending on the depth of the probe to be excavated, so the practitioner (doctor) should monitor the fluctuation of the meter pointer until the probe reaches the root apex 32 or root surface 33 of the tooth 30. You can tell whether it is close or not. At the above stage, the deflection of meter 8 is 40 (40 μA or
After confirming that the instruction is 20 μA), the next step is to measure the root canal length of the patient's tooth 30 being treated. In other words, switch S ₃ is returned to its original position by the force of the spring, so it is in the position shown (a contact), and switch S ₄ is in the position shown (except for the R test, and is interlocked with S ₅ ). ) from the input/output terminal 9 to the living body, and the probe 20 reaches the root apex 3.
2 or if the root surface 33 has not been reached, the output current is taken out from the input/output terminal 9 according to its depth, enters the operational amplifier ₆ via the switch S5, and after rectification is sent to the meter 8. . In this case, since the probe 20 has not reached the root apex 32, etc., a value smaller than 40, such as 36, is indicated.

In this way, the deflection of the meter 8 changes depending on how deep the probe 20 has reached, so if you proceed with the treatment by looking at the deflection of the meter, you will be able to avoid inadvertently passing a large current into the living body. It does not cause any pain to the patient. It goes without saying that when measuring the root canal length while expanding and exploring the pulp chamber, the crown pulp cavity and the upper part of the root canal should be dried so as to be electrically insulated from the gingiva.

Next, the case of diagnosing residual pulp will be explained. In this case, for example, press the R test button and briefly press switches S ₄ and S ₅ . Then, since patient S ₄ and switch S ₃ are interlocked, their arms are connected to the B contact, and a stabilized and fairly large DC current (for example, 40 μA) from Zener diode 3 flows into the arm of switch 5. is applied to the living tooth pulp from the input/output terminal 9 via the switch S ₄
The meter swings through the arm, but the swing of the meter at this time has no particular meaning. In this case, if there is any residue within the root canal 31, the patient complains of pain.

In addition, the method for diagnosing pulpitis using the device of Japanese Patent Publication No. 52-23507 mentioned at the beginning is the same as the method using the diagnostic device of the present invention, so the explanation will be omitted.

As described above, the dental diagnostic device according to the present invention uses a Zener diode to stabilize the voltage, uses an operational amplifier to perform stable oscillation and amplification, extracts a predetermined stable output current, and outputs a predetermined stable output current to the variable adjustment section. By eliminating the need for , operation is extremely simplified, measurement conditions remain constant, and accuracy and reliability are improved.

In addition, there is no fear of the adjustment knob being accidentally shifted as in the conventional case, and since the battery voltage drops rapidly, it is easy to check, and since an operational amplifier with low current consumption is used, the battery life is extended.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the dental diagnostic device according to the present invention, FIG. 2 is an external view of the device shown in FIG. 1, and FIG. 3 is a longitudinal sectional view of a tooth. In the figure, 1 and 2 are batteries, 3 and 4 are Zener diodes, 5 is a first operational amplifier forming an oscillator, 6 is a second operational amplifier forming an amplifier, and 7
is a rectifier, 8 is a meter, 9 is an input/output terminal, 10 is a connector (plug), 11 is a cord, 20 is a probe, 21 is an oral cavity guide, 22 is a root canal guide (reamer), 23 is a clip. Show each.

Claims (1)

[Claims] 1 Oscillator 5 that generates a predetermined oscillation output, R ₁ ,
C ₁ , R ₂ , C ₂ and the oscillation output from the oscillator are instructed to the meter as a predetermined reference value of the resistance of the human body through an amplifier, and then the oscillation output is applied to the human body through the electrode, and the oscillation output from the oscillator is switch means S ₃ , S ₄ , S ₅ configured to direct an amplified output taken through the resistor to the meter, prior to measuring the depth of the root canal between the electrodes; and automatically sets a current at a predetermined level representing the predetermined reference value at the first position of the switch means ( _S3 is the B contact, _S4 is the A contact, and _S5 is the A contact), and the current is applied to the meter. Then, the oscillation output is applied to the human body at the second position of the switch means (S ₃ is the a contact, S ₄ is the a contact, S ₅ is the a contact), and the resistance change of the human body existing between the electrodes is caused. , Therefore, the dental diagnostic apparatus is characterized in that the depth of the root canal of the tooth existing between the electrodes is detected from the change in the deflection of the meter corresponding to the current change.