JPH0325175B2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a tooth vibration diagnostic device used for diagnosing the occlusal state of upper and lower teeth during prosthetic treatment in dental treatment, and measuring and diagnosing the degree of tooth movement. It is.

(Prior Art) One of the conventionally known devices of this type is an occlusal sound measurement device that displays occlusal sound waves generated during occlusion of upper and lower teeth as vibration waveforms on, for example, a cathode ray tube screen. There is a device.
Specifically, the occlusal vibrations generated during occlusion of the upper and lower teeth are transmitted from the teeth to the cheekbones via the jawbone and extracted as bone-conducted sound, and this bone-conducted sound is detected by a microphone or vibration sensor pressed against the face above the cheekbones. It is picked up as an electrical signal, converted to a digital signal by an A/D converter, then stored in memory, and the stored signal is restored to the original analog signal by a D/A converter and reproduced on the screen of a cathode ray tube. This is how it was done.

In the above device, the occlusal condition is determined based on differences in the signal waveform displayed on the CRT screen, such as duration, envelope shape, or the presence or absence of double or triple sounds in which simple waveforms repeat, and occlusal adjustment is required. The purpose of the test was to identify the most important parts of the body and determine the necessary treatment.

On the other hand, conventionally known methods for measuring and determining the degree of tooth movement include subjectively sensing the degree of movement when the dentist moves the target tooth with tweezers, etc. The most common method is to judge the degree of agitation based on the primitive method. In addition, a differential transformer or the like is used to detect the vibrations generated in the teeth as an electrical signal when an impulse impact is applied to the teeth through a plunger or the like.
Electric diagnostic devices that display the information on a display are also known. Furthermore, it has been proposed to apply a measuring device that is an integrated vibrator and impedance head to the tooth to detect the vibration state.

(Problems to be Solved by the Invention) Among the conventional devices described above, the occlusal sound measuring device picks up vibrations as bone-conducted sound at the facial position above the cheekbones, and is designed to pick up vibrations caused by tooth occlusion. Because the generation point and the pick-up point are far apart, the generated vibration varies greatly depending on individual differences in the propagation path to the pick-up point, and even if a particular tooth is in abnormally strong occlusion, It was difficult to determine whether the occlusal force being applied was abnormal or normal, resulting in a lack of accuracy in diagnosis.

Furthermore, since the pick-up points are two points on the left and right sides of the face, the different vibrations caused by the occlusion of many teeth are mixed together and picked up, making it difficult to determine which teeth are making abnormally early contact or which teeth are being picked up. However, the occlusal vibration becomes a double sound accompanied by sliding, making it impossible to determine whether the patient has an abnormal occlusion at all, and the initial diagnosis is left to the dentist's empirical judgment despite the use of a device. I had a problem.

Furthermore, among the means for measuring and determining the degree of tooth movement, methods based on the dentist's finger sensations require a great deal of experience and are insufficient in terms of diagnostic reliability.

Furthermore, when using the above-mentioned electrical diagnostic equipment, a fairly strong impulse impact is applied to the teeth, which not only causes physical and mental pain to the patient, but also causes inflammation of the periodontal tissue. The drawback was that it could not be applied as a practical matter in cases such as these.

Furthermore, with measuring instruments that integrate a vibrator and an impedance head, the head directly picks up vibrations and noise from the vibrator, making it possible to separate signals indicating tooth condition from the detected signals for accurate diagnosis. Furthermore, since the vibrations are applied continuously, it is not suitable for detecting the vibrations that occur during occlusion, and it is considered that the condition of the teeth cannot be diagnosed from the state of vibration attenuation. Another problem is that the measuring device is large and cannot be used for purposes such as detecting and comparing the vibration states of multiple teeth individually and simultaneously.

This invention was made in view of the above-mentioned circumstances, and it is possible to accurately and easily diagnose tooth occlusion, and also to properly and accurately diagnose the degree of tooth movement without causing pain to the patient. The purpose is to provide diagnostic equipment.

(Means for Solving the Problems) In order to achieve the above object, the tooth vibration diagnosis device according to the present invention can be fixed to or pressed against the side surface of the tooth, and in this fixed state or pressed state, tapping or Equipped with an acceleration sensor that detects tooth vibration due to percussion, a circuit that generates an electric signal proportional to the acceleration of tooth vibration caused by this acceleration sensor, a memory that stores the output signal of this circuit, and a display device that displays it. It is characterized by its structure.

(Function) When using the tooth vibration diagnosis device according to the present invention having such a characteristic configuration, (a) Tapping the upper and lower teeth with the acceleration sensor fixed to the side surface of one or more teeth; (b) The acceleration sensor is fixed to the side surface of one or more teeth, and the force transducer is used to vibrate the target tooth using a built-in vibration hammer, etc. (c) The acceleration sensor is attached to the dental Tapping the upper and lower teeth while pressing the acceleration sensor against the side surface of the tooth using the dentist's fingers, etc. (d) Tapping the target tooth with the acceleration sensor pressed against the side surface of the tooth using the dentist's finger, etc. Tooth vibration is detected by the above-mentioned acceleration sensor by vibrating the tooth using a vibrating hammer or the like.

Generate a voltage proportional to the tooth vibration speed by integrating once the signal voltage proportional to the tooth vibration acceleration from such an acceleration sensor, or integrate the signal voltage proportional to the tooth vibration acceleration twice. A voltage proportional to tooth vibration displacement is generated, and these voltage signals are stored in a memory and displayed on a display.

By observing the voltage signal waveform displayed on such a display, you can determine whether the occlusal state is abnormal or normal, which teeth are making abnormally early contact, etc. A comprehensive diagnosis is performed.

In particular, the tooth mechanical admittance ( By calculating the reciprocal of mechanical impedance and displaying it on a display, or by dividing the tooth vibration displacement value obtained by integrating the tooth vibration acceleration twice by the force transducer output, By determining a value proportional to the stiffness of the tooth and displaying it on a display, the degree of tooth movement, including the degree of attachment of the tooth to the jawbone and the degree of tooth support, can be diagnosed.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

First Embodiment In FIGS. 1 to 4, 21 is an ultra-small acceleration sensor, and double-sided tape 218 is attached to the sides of a total of eight teeth 11, four on the left and right of the upper jaw, among the upper and lower teeth of the patient 1. These eight acceleration sensors 21 are connected to the input terminals of the eight channels of the main body 31 through ultrafine coaxial cables 211, and the acceleration sensors 21 are connected to the input terminals of the eight channels of the main body 31 through ultrafine coaxial cables 211. A signal is input to the main body 31 via the coaxial cable 211, and this is
It is configured to be displayed on a CRT display 32.

Reference numeral 22 is a lightweight and thin acceleration sensor, which is fixed to the center of the forehead of the patient 1 with double-sided tape or a wide elastic belt, and connected to the main body 31 via a coaxial cable 221 for triggering during tapping vibration.
is connected to the trigger terminal of the

As clearly shown in FIG. 4, each acceleration sensor 21 is constructed by sequentially stacking an electrode 217, a piezoelectric element 216, an electrode 217, and a piezoelectric element 216 on a sensor base 213, and attaches the electrode 217 to the base 213 via a weight bolt 215. Tighten and fix the above two electrodes 21.
The ultrafine coaxial cable 211 is pulled out from the case 7, 217, and the piezoelectric elements 216, 216, electrodes 217, 217, and weight bolt 215 are connected to the case 2.
It has a structure surrounded by
m/s) or less, and the optimal sensitivity direction is the buccolingual direction, but the vibration in the vertical direction of the tooth may also be measured in the tooth axis direction.

Further, as a means for fixing the acceleration sensor 21 to the side surface of the tooth 11, a curved surface along the side surface of the tooth 11 and a flat surface that abuts on the base 213 of the acceleration sensor 21 are provided from the target tooth of the patient 1 in the model. core 2
The acceleration sensor 21 is fixed to the flat surface of the core 212 with an instant adhesive or the like.
The double-sided tape 218 is attached to the curved surface of the tooth 11. However, if it is difficult or insufficient to adhere with the double-sided tape 218 alone due to unevenness on the side surface of the tooth 11, there may be a gap between the double-sided tape 218 and the side surface of the tooth 11. Adopt a method of supplementary filling with dental adhesive to obtain sufficient adhesion.

FIG. 5 schematically shows a circuit that generates an electric signal in proportion to the acceleration of tooth vibration by the acceleration sensor 21, and is housed in the main body 31.

In FIG. 5, X1 is a charge amplifier, which consists of an operational amplifier Q1, a resistor R1, and a capacitor C1.
and converts a charge signal proportional to the acceleration of tooth vibration from the acceleration sensor 21 into a voltage signal. This voltage signal output is led to the switch SW1 via the coupling capacitor C2, and is also led to the integrating circuit X2 consisting of an operational amplifier Q2, resistors R2 and R3, and a capacitor C3, where it is proportional to the tooth vibration acceleration. The resulting voltage is integrated and converted into a voltage proportional to the tooth vibration speed.
This voltage output is led to the switch SW1 via the coupling capacitor C4, as well as to the next stage operational amplifier Q3, resistors 4 and 5, and the capacitor C5.
The voltage is guided to an integrating circuit X3 consisting of , where it is integrated again, and the voltage proportional to the tooth vibration speed is converted into a voltage proportional to the tooth vibration displacement, and the voltage is then led to the switch SW1.

The above-mentioned switch SW1 can be selectively selected from three methods: tooth vibration acceleration measurement, tooth vibration velocity measurement, and tooth vibration displacement measurement.The signal voltage at the common terminal of this switch SW1 is converted into a digital signal by the A/D converter 301. It is then input to a PPI or PIO programmable peripheral interface 302.

On the other hand, the charge output of the trigger acceleration sensor 22 is input to the trigger terminal, and the operational amplifier Q4
is inputted to a charge amplifier Y consisting of a resistor R6 and a capacitor C6, and is converted into a voltage signal.
The trigger voltage signal is guided to the A/D converter 201, converted into a digital signal, and then input to the interface 302.
11, R12 and a variable resistor R10, a window comparator circuit Z generates a trigger signal in response to a bone conduction sound of a predetermined level or higher.

This trigger signal output is input to the interface 302, and using this trigger signal as a reference, 8 channels of digital signals related to tooth vibration are stored in the memory 304 through the control of the CPU 303, and this stored data is sent to the CRT controller 305. is converted into a video signal by CRT
displayed on the display 32. Further, data is sent as a digital signal to a digital recorder or a personal computer via the peripheral interface 306 as required.

The actual A/D conversion sampling rate is
The optimal value is 5 μs/word to 20 μs/word, and a minimum of 10 ms is required to store the tooth vibration caused by one tapping from the start of the vibration to the end of the vibration.

Figure 11 shows an example of the display of tooth vibration measurement on a CRT display.The horizontal axis represents time, which is 10ms for the entire interval, and the vertical axis represents tooth vibration acceleration. ,CH
2,...CH8 and 8 channels are displayed. In addition, the digital signal data of the tooth vibration may be obtained by using the signal of the trigger acceleration sensor 22 as the vibration start reference point as needed, and at a point slightly back in time from this vibration start point, that is, with a negative delay. The data is averaged multiple times and displayed on a CRT display starting from an early point in time, around 100 μs, which is the time it takes for tooth vibration to reach the center of the forehead via bone conduction.

Looking at the vibration waveforms for 8 channels shown in Fig. 11, by drawing a broken line at the peak of the maximum waveform, we can see that the tooth vibration acceleration waveform of CH4 occurs earlier in time and has a larger amplitude. Therefore, it can be visually confirmed that the tooth corresponding to CH4 is in abnormally early contact. In addition, the waveform of CH5 has a delayed start point and a small amplitude. Therefore, the tooth corresponding to CH5 is not properly engaged and vibrates only due to the bone conduction of the jawbone compared to the adjacent tooth. It can be determined that

Note that in the first embodiment, the use of the trigger acceleration sensor 22 is not absolutely essential, and it may be omitted.

Second Embodiment In FIGS. 7 and 8, reference numeral 41 denotes a ring-shaped fixture made of spring material;
1, an acceleration sensor 4 in which an electrode 43, a piezoelectric element 44, an electrode 43, and a piezoelectric element 44 are laminated in order through a base case 42 made of stainless steel is fixed by tightening with a weight bolt 45 for finger diagnosis. A model tooth vibration diagnostic device is constructed. In the figure, reference numeral 46 denotes an ultra-fine coaxial cable, which extracts the acceleration of tooth vibration by the acceleration sensor 4 as a charge output proportional to the acceleration and inputs it into the main body 31.

As shown in FIG. 7, such a finger examination type tooth vibration diagnosis device is constructed by fitting the fixing device 41 on the fingertip of a dentist, and as shown in FIG. Press lightly with enough force to not interfere with tooth vibration. In this state, the patient taps the teeth, and the acceleration sensor 4 detects the acceleration of the tooth vibration, which is stored in the memory in the main body 31 (not shown) via the coaxial cable 46.
Normally, to improve measurement accuracy, a single tooth is measured several times, and the average value is stored in the CPU.

Then, the memory area is automatically or manually shifted, and the same measurement and data storage are performed by pressing the tooth against another tooth. This process is performed sequentially for eight or more teeth, and if necessary, as in the case of the first embodiment, the electric circuit shown in FIG. 5 is used to obtain tooth vibration velocity data and tooth vibration displacement. It can also be stored as data.

In the case of this second embodiment, the trigger acceleration sensor 2 is placed at the center of the forehead of the patient 1 during measurement.
2 is indispensable to ensure measurement accuracy.

Third Embodiment This third embodiment relates to the measurement of the degree of tooth movement, and similarly to the first embodiment shown in FIGS. 1 to 4, the acceleration sensor 21 is connected to the tooth 1 as shown in FIG.
1, and then the side surface of the crown part of the target tooth 11 is struck with an impact hammer 5 having a force transducer inside. Both this striking force and the acceleration of tooth vibration are stored.

FIG. 10 shows the internal structure of the percussion hammer 5, in which the hammer weight/base 52 has an electrode 53,
A piezoelectric element 54, an electrode 53, and a piezoelectric element 54 are laminated in this order, and are fastened and fixed by a chip base bolt 55, and a vibration chip 51 made of resin is fixed to the tip thereof. A coaxial cable 58 that outputs a force transducer proportional to the vibration force is inserted and held inside the .

Figure 12 shows the CRT of the degree of tooth movement according to this example.
An example of the display on the display is shown. In the figure, the voltage after integrating the tooth vibration acceleration due to percussion and converting it into a signal proportional to the vibration speed by the integrating circuit X2 shown in FIG. Divided by the peak value of the force transducer output in the hammer 5, the tooth vibration velocity signal for a predetermined force, that is, the tooth mechanical admittance, is displayed on the CRT display. In addition, if the dentist is unable to sufficiently strike the tooth 11 with the hammer 5, or if the strike is too strong, the data will be canceled and not stored in the memory, and the data will be within an appropriate range. Only the data on the striking force is taken and the data is averaged over the number of times and displayed. Furthermore, at the same time as marking the first peak, the peak value is transferred to the left channel.
By displaying it next to the number, it is possible to further facilitate tooth diagnosis.

In the display example in Fig. 12, the first peak value of CH3 is the largest, the admittance is large, and it can be determined that the degree of movement is high, and the first peak value of CH2 is extremely low, the degree of movement is very low, and the tooth The possibility of adhesion with the jawbone can be determined.

As another example of the display, the voltage signal corresponding to the tooth vibration acceleration is integrated twice to obtain a signal corresponding to the tooth vibration displacement, and this is divided by the peak value of the vibration force to calculate the mechanical stamina. It is also possible to determine the corresponding value and display it on a CRT display for diagnosis.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, tooth vibration caused by tapping or percussion is transmitted through a relatively long propagation path such as bone conduction, which differs from person to person. Since it is possible to directly detect tapping or impacting teeth without having to do so, it is possible to accurately and easily diagnose tooth misalignment, such as finding teeth with abnormal occlusion, early contact, and finding teeth with sliding. can be done.

In addition, since vibration is applied by tapping or percussion and the vibration is detected by an independent acceleration sensor, the vibration exciter generates a signal that indicates the condition of the tooth, as if the vibration exciter and sensor were integrated. Since the vibrations and noise of the device are not directly detected, it is easy to perform an accurate diagnosis, and it is also possible to apply a single vibration and perform a diagnosis from the damped state of the vibration.

In addition, since the acceleration sensor can be miniaturized, it is possible to place the acceleration sensor individually on multiple teeth, and as in the example, the detected signal waveforms can be displayed simultaneously and compared, allowing comprehensive diagnosis. can be done.

Moreover, when diagnosing the degree of tooth movement, there is no need to apply strong impulses to the teeth, and only a light pressure or vibration is required, so it is appropriate and safe to diagnose the degree of tooth movement without causing physical or mental pain to the patient. This has the remarkable effect of making it possible to diagnose the degree of agitation.

[Brief explanation of drawings]

1 to 5 show the first embodiment,
Figure 1 is a conceptual diagram showing the diagnostic procedure, Figure 2 is a front view of the main parts showing the state of the acceleration sensor being stuck, Figure 3 is a plan view of Figure 2, Figure 4 is an enlarged sectional view of the acceleration sensor, Figure 5 is an electric circuit diagram, Figures 6, 7 and 8 show the second embodiment, Figure 7 is a plan view of the main parts showing the state of installation during diagnosis, and Figure 8 is a diagram of the main parts. 6
Fig. 6 is a conceptual diagram showing the diagnostic procedure, Fig. 9 and Fig. 10 show the third embodiment, and Fig. 9 is a side view of the main part of the diagnostic procedure. 1
Figure 0 is an enlarged cross-sectional view of a percussion hammer, Figure 11 is an example of how tooth vibration due to tapping is displayed on a CRT display, and Figure 12 is an example of tooth movement due to tapping.
This is an example of a display on a CRT display. Explanation of symbols, 21... Acceleration sensor, 32...
CRT display (display device), 304...memory, X1, X2...integrator circuit.

Claims (1)

[Scope of Claims] 1. An acceleration sensor that can be fixed to or pressed against the side surface of a tooth and that detects tooth vibration due to tapping or striking in the fixed or pressed state, and A tooth vibration diagnostic device comprising a circuit that generates an electrical signal proportional to acceleration, a memory that stores the output signal of the circuit, and a display device that displays the output signal. 2. The electric signal generation circuit is an integral circuit that generates a voltage proportional to the tooth vibration acceleration by the acceleration sensor, or generates a voltage proportional to the tooth vibration displacement obtained by re-integrating the signal voltage proportional to the tooth vibration speed. A tooth vibration diagnostic device according to claim 1, which is constructed as follows.