JPH0618579B2 - Hammer for measuring tooth mobility - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a hammer used in a measuring device for estimating tooth health by measuring tooth mobility.

(Prior Art) In each field of dentistry, the measurement of tooth mobility is a particularly important matter as a means for estimating the health condition of teeth. For example, in the design of a prosthesis, it is indispensable for diagnosis and prognosis observation of abutment teeth, and in periodontal disease, it is a diagnostic method that cannot be ignored for determining a treatment method. Therefore, attempts have been made to accurately diagnose the degree of health of teeth and periodontal tissues. For example, palpation, blindness measurement, percussion, X-ray image, etc. are used as clinical judgment methods.
As a device for measuring tooth mobility, the dial gauge method, strain gauge method, electric differential transformer method, which represents the amount of tooth displacement with respect to external force, the method of measuring tooth movement by reflecting it with a small mirror, and applying vibration There are a resonance frequency measuring method and a mechanical impedance measuring method for obtaining the response characteristic.

(Problems to be Solved by the Present Invention) However, in clinical application, these devices have many problems such as a large-scale device, data reliability, and difficulty in fixing an exciter. Is currently using a method in which the degree of tooth vibration is classified into four stages from 0 degree to 3 degrees by a mirror measurement method using an empirical sense. This measurement method has a drawback that it is largely influenced by the subjectivity of the operator, and since it emphasizes only the amount of tooth displacement, it does not mean that the properties of the periodontal tissue such as viscoelasticity of the periodontal tissue cannot be clarified. there were.

Therefore, as a device for electrically measuring the degree of vibration of teeth,
In a tooth mobility measuring device that catches a vibration waveform generated by hammering a tooth and draws this as a visible vibration waveform on a CRT, the head of an acceleration pickup hammer that catches the hammering sound of the tooth Was devised, the accelerometer used in this device responds too sensitively, and it is essential for various factors other than shaking (eg pickup weight, condition of crown treatment). I couldn't catch the upset. Since the head of the hammer was made of metal, the high frequency component of the metal itself added to the vibration waveform caused by the hammer impact, and the waveform was discontinuous and cracked. It was

The present invention has been made in view of the drawbacks of the conventional example, and an object thereof is to provide a hammer for measuring tooth mobility that is capable of collecting an accurate and easy-to-see vibration waveform of a tooth without the weight of noise. is there.

(Means for Solving Problems) In order to solve the above-mentioned conventional problems, the present invention is directed to; in the first invention; a vibration waveform that is generated by hammering a tooth and is visually observable. In a tooth mobility measuring device that is drawn on a CRT (7) as described above, a microphone (1) for catching a hammering sound of a tooth is incorporated in a head (2a) of a hammer (2).

Is adopted as a technical means.

(Operation) First, a patient's tooth is hammered with a hammer (2).

Then, the hammering analog signal is caught through the microphone (1) attached to the hammer (2).

At this time, since the head (2a) of the hammer (2) is made of synthetic resin, the high frequency component of the metal itself does not weight, and only a pure hammering analog signal is caught.

This caught hammering analog signal is amplified and
It is sent to the / D converter (3), converted into a hammering digital signal, and then sent to the write-only storage device (4a).

This A / D converter is used for the write-only memory device (4a).
The hammering digital signal is written from (3), and at the same time, the hammering digital signal is transferred to the display storage device (4b) built in the main controller (5).

The hammered digital signal transferred to the display storage device (4b) of the main controller (5) is finally converted to an original analog signal in a clear form with fine vibrations removed through a CRT controller (6), and the CRT is then displayed. (7) Top hammered analog waveform (32) (33)
Is reproduced as.

The initial wavelength “usually the first wavelength (5a)” of the hammering analog waveforms (32) (33) is measured to determine the degree of tooth vibration.

(Examples) Hereinafter, the present invention will be described in detail with reference to illustrated examples. In the block circuit diagram of FIG. 1, (2) is a hammer, and the material of the head (2a) is polyoxymethylene resin which is largely deviated from the resonance frequency of the teeth.

What should be considered about hammer (2) is that it is possible to clearly distinguish the difference between a healthy tooth and an oscillating tooth, it is easy to operate as a diagnostic tool, it does not change variously after repeated use, and for disinfectants etc. And stable.

(1) is, for example, an omnidirectional microphone (not limited to this, of course), which is mounted on the side surface of the hammer (2), and is, for example, 50 Hz to 15 KHz (not limited to this, of course). .) Frequency characteristics. Urethane may be interposed between the hammer (2) and the microphone (1) to prevent generation of scratching noise as much as possible. (11) is the first amplifier, (12) is the second amplifier, the microphone
It is connected in series to (1). (9a) (9b) (9c) are three types of comparators, and the output of the first amplifier (11) and three types of reference potentials (8a)
(8b) Compared with (8c), hammering strength "strong""pass"
The judgment is "weak". Also, if the hammering strength is "passed", it will be displayed to the operator by the pass indicator (10) provided on the hammer (2) (for example, this is displayed by turning on the LED). The work is facilitated to speed up the work.

The output of the second amplifier (12) is connected to the A / D converter (3), and further connected to the main controller (5) via a write-only storage device (4a) consisting of a random access memory.

The main controller (5) has a central function of controlling commands from the control panel (13), computing the first wavelength (S) of the hammering waveform, etc., and a 2-channel display storage device (random access memory) 4b) is provided.

(6) is a CRT controller, X of the main controller (5),
It is connected to a Y output terminal, and further connected to a CRT (7) for controlling the CRT (7) in X and Y axes and controlling brightness (Z control).

(13) is a control panel, which is a repeating / fixing button switch (14) for selecting whether to update or fix the hammering digital signal, and selects the length of the time base (in other words, a 1 msec hammering analog signal). Is selected to be displayed as 1 cm to 2 cm on the CRT (7).) 1m / 2msec switching button switch (15), channel selection button switch (16) for selecting either 1 or 2 channels, Main controller is the length of the first wavelength (S) of the hammering analog waveforms (32) (33) drawn on the print start button switch (17), paper feed button switch (18), and CRT (7) Make it longer than the calculation result of (5) (In other words, the first wavelength (S) is drawn brighter on the CRT (7) than other parts for easier viewing. Up button switch (19), Button switch down for shortening the first wavelength (S) to the fine reverse
(20), 1st and 2nd channel image raising and lowering volumes (21) (22), CRT (7) for raising the hammering analog signals of the 1st and 2nd channels drawn on the CRT (7)
A horizontal movement control (2) for horizontally moving the hammering analog signals of the first and second channels drawn above.
3), and includes a brightness adjusting volume (24) for adjusting the brightness of the light brightness part of the first wavelength (S). The repeat / fixed button switch (14) to the paper feed button switch (18) and the first and second channel image raising / lowering volumes (21) (22) are input to the main controller (5). However, the hammering analog waveform (32) (3
The up volume (21) for the operator to adjust the length of the first wavelength (S) in 3) and the down volume (22) for shortening the first wavelength (S) are up / down. Down counter
Main controller via (25) and digital comparator (26)
Input is made to the display storage device (4) of the first or second channel of (5). Brightness control volume (24)
It is connected to the Z terminal of the CRT controller (6) through the Z controller (27).

(28) is the scale display section for the first wavelength (S) of the hammering waveform.
Through the ED driver (29), numerical values up to the last two digits are displayed based on the calculation result of the main controller (5).

(30) is a printer, which is connected to the main controller (5) and can be operated by operating the buttons on the control panel (13).
Input to the display storage device (4b) in (5) (in other words,
The hammered analog waveforms (32, 33) (displayed on the CRT (7)) are printed out.

Reference numeral (31) is a power supply for the apparatus, which supplies power to the CRT controller (6), the main controller (5) and others.

Reference numeral (7) is a CRT, which is connected to the CRT controller (6) and is adapted to perform XYZ control.

When the hammer (2) hammers a tooth, the hammering sound is caught by the sensor (1) as a hammering analog signal.

When a hammering analog signal is input to the sensor (1), it is converted into a hammering digital signal through the first and second amplifiers (11) (12) and the A / D converter (3), and a write-only storage device. (4a)
To be stored in the display storage device (4b). At the same time, the hammering analog signal branched at the output side of the first amplifier (11) enters the three types of comparators (9a) (9b) (9c),
Compared with the respective reference potentials (8a) (8b) (8c), pass / fail judgment of hammering strength is performed, and judgments of "strong", "pass" and "weak" are displayed. L provided on the hammer (2)
The ED is lit up. If the hammering strength is too strong or too weak, the tooth is hammered until a pass judgment is made, and the hammering digital waveform data that finally passed is left in the display storage device (4b). . Experimental result 0.3G ~ 0.
It has been found that an exciting force within the range of 8 G does not produce a result that affects the first wavelength. This data is immediately transferred to the CRT controller (6) and then passed through a filter (not shown) to cut a thin vibration waveform, which is then D / A converted to make it easy to see the original analog waveform (32 )
CR restored to (33) and used as display (28)
It is input to T (7) and reproduced as hammering analog waveforms (32) (33) on the display surface of the CRT (7). The CRT (7) is used as a multi-phenomenon (two phenomena in this embodiment) by the chopping circuit built in the CRT controller (6), and CR
The hammering analog waveforms (32) and (33) of the first and second channels are drawn on T (7) by switching channels. Of course, it is possible to display only one waveform if the channel is not switched, and the printer (30) is operated by the command of the main controller (5) and the data of the display storage device (4) is drawn on the recording paper. You can also do things. Further, the CRT controller (6) also does not function as a vibration waveform moving device, and the left and right hammering analog waveforms (32) (33) drawn on the CRT (7) are moved up and down by operating the buttons or the volume of the control panel (13). -It is also possible to move the left and right separately to adjust the position, and it is also possible to make the diagnosis easier by placing them close to each other or overlapping.

As described above, the hammer (2) vibrates the tooth, the sensor (1) receives it, and collects the tooth vibration sound, and reads the length of the first wavelength from the rise of the impact on the time axis. , To measure the tooth mobility.

Fig. 3 (a) shows the hammering analog waveform (32) of a healthy tooth.
(b) is a hammering analog waveform (33) of the wobbling tooth, in which the wobbling tooth has a longer first wavelength (S).

In the above embodiments, only the block diagram is shown, and regarding the concrete connection of each block, what is considered to be the most suitable for exhibiting the functions as described above is appropriately selected and adopted.

<Example 1> (1) Weight of hammer A hammer using a poly-exmethylene resin for the head (hereinafter referred to as POM hammer) is "36.5 g", "37.8 g", "40.
"4g", "46.4g", "51.1g", hammers using metal for the head (hereinafter referred to as metal hammer) are "17.6g", "18.6"
Five kinds of "g", "19.2g", "22.8g", and "24.6g" were prepared as described above.

(2) Subject 1 rubber sheet with a thickness of 0.2 mm and 3 rubber sheets (thickness approx.
0.5 mm) was adhered and this was planted in a plaster block. A small accelerometer (weight 0.65g) is attached to the side of each hammer that is opposite to the percussion side, and a microphone (weight 3.0%) is attached to the side.
g) was installed, and the percussion sound was measured by hammering with a size of 0.3 G while monitoring the labial central part of the crown of the tooth to be examined with a level indicator.

[Experimental Results] FIGS. 3 (a) to 3 (d) are time-axis waveforms printed out. The upper rows (a) and (b) show the information from the accelerometer attached to the head of the hammer, the lower rows (c) and (d) show the information from the microphone, and the first wavelength (S ₁ ) (on the time axis of the lower row) S ₂ ) (S ₃ )
(S ₄ ) is the data indicating the degree of tooth vibration. The maximum value in POM hammer is 3.234 msec for the swaying tooth 51.1 g, and the minimum value is
It was 1.591 msec with 40.4 g of healthy teeth. The maximum value for a metal hammer is 3.031msec for the rocking tooth 24.5g, and the minimum value is a healthy tooth.
19.2 g was 1.648 msec. Considering Fig. 4, which is a graph of these results, the POM hammer is 40.4g to 5
Up to 1.1g, there is a constant difference between the swaying teeth and the healthy teeth, but there is a proportional increase, but the weight less than that gives similar results regardless of the swaying teeth and the healthy teeth.
It is presumed that this is because the head of the hammer is hard to work for a hammer having a small weight and the vibration force to the subject becomes insufficient. The first wavelength (S) except 24.6g for metal hammer
Exists between 1.6 and 2.3 msec, and is the first of the shaking and healthy teeth.
The difference in wavelength (S) is smaller than that of POM hammers.

In addition, comparing the metal hammer and the POM hammer, both have a difference in the first wavelength (S) due to the difference in the degree of tooth vibration.
In a metal hammer, a high frequency component of the metal itself appears on the waveform [Fig. 3 (b)], and one wavelength is discontinuous and broken, so the waveform becomes difficult to see.

In addition, when the weight of the entire hammer was light or the weight of the head was too small compared to the handle, the balance at the time of percussion was poor and hammering was difficult. From the above results, it was found that polyoxymethylene resin is the best material for the head of the impact hammer and that the weight of the POM hammer is 40.4 g.

<Example 2> Influence of thickness of artificial periodontal ligament One possible cause of tooth sway is expansion of periodontal ligament.
In order to know the relationship with the size of the periodontal ligament, the number of rubber sheets as artificial periodontal ligament was changed and its effect was examined.

[Experimental method] Artificial tooth A total of 7 types of tooth to be inspected, in which 1 to 6 rubber sheets were adhered to the tooth root portion, and 7 types of artificial teeth to which the rubber sheet was not adhered, were planted in a gypsum block and used as the subject. Each sample was struck 30 times and the result was obtained. The thickness of the artificial periodontal ligament is 0.20 mm for one sheet and 0.35 m for two sheets.
m, 3 pieces 0.50mm, 4 pieces 0.60mm, 5 pieces
It was 0.75 mm and 0.96 mm for 6 sheets.

[Experimental results] Significant differences were observed between each tooth to be examined (Fig. 5), the minimum value is 1.799 msec when the artificial periodontal ligament is 0 mm, and the maximum value is artificial periodontal ligament 0.9.
At 3.427 msec of mm, the first wavelength became longer as the thickness of the artificial periodontal ligament increased. When the correlation between the thickness of the artificial periodontal ligament and the first wavelength was determined based on the average value of the measurement results, the sample correlation coefficient (P) was 0.982.

Estimated correlation coefficient from this sample correlation coefficient, I asked for. If the estimated correlation coefficient is greater than t (degree of freedom, 0.01), there is a highly significant correlation. The obtained estimated value was greater than 11.62 ≧ t (5,0.01) = 4.03, so that there was a true correlation between the thickness of the artificial periodontal ligament and the first wavelength.

<Example 3> Resorption of marginal alveolar bone of tooth root As factors of tooth sway, enlargement of periodontal cavity and resorption of alveolar bone edge are considered. In this section, the experiment was conducted assuming the resorption of alveolar bone by changing the amount of artificial teeth planted in the plaster block.

[Experimental method] Three types of artificial periodontal ligament thickness (0.2 mm, 0.35 mm, 0.50 mm) were placed in a gypsum block, and plaster was removed from the cervical part at intervals of 2 mm up to 10 mm. This was used as a sample and was percussed three times.

[Experimental Results] According to the average value of the experimental results, the thicker the artificial periodontal ligament and the less the coverage of the root of gypsum, the longer the first wavelength,
It showed an upset tendency. Examining the graph of the measurement results in FIG. 6, it was found that in the artificial periodontal ligament 0.20 mm, a significant difference could not be recognized from 0 to 6 mm in the horizontal defect of the alveolar margin, but it reached 8 or 10 mm. Then, the first wavelength suddenly became longer and a significant difference was observed, but almost no significant difference was observed between 8 mm and 10 mm. In the artificial periodontal ligament 0.35 mm, no significant difference was observed between the horizontal alveolar margin 0 and 2 mm, but in the amount of deletion more than that, a significant difference was observed in all. In the artificial periodontal ligament 0.50 mm, no significant difference was observed between the alveolar margin horizontal defects of 4 mm and 6 mm, but in all other cases, a significant difference was observed.

Overall, 0.50 mm artificial periodontal ligament horizontal defect 2 mm to 4 mm, 0.35 mm artificial periodontal ligament horizontal defect 4 mm to 6 mm, 0.20 mm artificial periodontal ligament horizontal defect A sharp change occurred between 6 mm and 8 mm, and the first wavelength was increased by 2 to 3 msec. It is speculated that the relationship between the enlargement of the periodontal space and the resorption of the alveolar bone margin has a great influence on the motion of the tooth. In contrast, when the periodontal ligament is enlarged, the resorption of the alveolar bone margin appears as a remarkable sway.

Since the total length of the root is 16 mm, in the case of artificial periodontal ligament 0.20 mm, if the horizontal absorption of the alveolar bone margin is within 38% of the total root length, there is no big change in the first wavelength and there is a large difference in the planting state. There will be no. Similarly, in the case of artificial periodontal ligament of 0.35 mm and 0.50 mm, it is considered that when the horizontal absorption of the alveolar bone margin exceeded 12.5% of the total root length, the first wavelength became abruptly longer and the planting condition deteriorated. .

<Example 4> Comparison between healthy teeth and oscillating teeth in dry mandible In the above model experiment, the first distinction between healthy teeth and oscillating teeth was made.
It could be represented by the difference in wavelength. Therefore, the experiment in this section was conducted in order to bring it closer to the clinical situation.

[Experimental method] (1) Subject Two adult dry mandibular bones were extracted with ▲ ｜ ▼, silicone impression material was injected into the extraction socket, and each tooth was restored to its original position to be a healthy tooth. did.

The lip-lingual thickness of the artificial periodontal ligament is it is conceivable that.

Next, the alveolar bone wall of the tooth extraction fossa was removed with a bone bar, the periodontal cavity was enlarged to create a state of swaying from a healthy tooth, and a silicon impression material was injected, and then the tooth was inserted.

The lip-lingual thickness of the artificial periodontal ligament is it is conceivable that.

[Experimental Method] From the results of the model experiment described above, a POM hammer (40.4 g) was applied to the subject with a percussion force of 0.3 G at the labial central part of the crown. The number of times of vibration was set to 3 for each item, and analysis was performed using a 2-channel tooth mobility measuring device.

[Experimental Results] As a result of the measurement, the healthy tooth group showed a tendency similar to that of the healthy tooth group, although the first wavelength of the canine tooth was longer. Observation of the measurement results in a graph in Fig. 7 shows that There was a significant difference between the healthy and swaying teeth in all but the teeth. In the healthy teeth group, the first wavelength of NO.1 subject is 1.8
71msec to 3.153msec, that of NO.2 subject is 1.607msec
Between 2.690 msec. Also, in the rocking tooth group, NO.
It was 2.029 msec to 5.467 msec for one subject and 3.366 msec to 6.693 msec for the NO.2 subject. As described above, the bone transplantation state of the human adult dry mandible could be grasped, and the first wavelength tended to be longer in the tooth species with a short root length than in the tooth species with a long root length.

[Example 5] Effects of various prosthetic restorations In clinical practice, various prostheses are often attached to the tooth to be examined. We examined how the restorations of the crown affected the measurement of their mobility.

[Experimental method] NO.1 After forming the abutment tooth, porcelain crown, range crown,
Each of the metal crowns was made. Each dental prosthesis was made to have the same size as possible using a core, and these were temporarily attached by a temporary pack at the time of measurement. The artificial periodontal ligament used a silicon impression material, but the thickness is As an upset tooth Met.

[Experimental Results] FIG. 7 shows the EFT analysis results, and FIG. 8 shows the measurement results in a graph. As shown in FIG. 8, the effect of the difference in prosthesis was not recognized in the healthy tooth group, and the first wavelength also showed a value smaller than that of the rocking tooth. In the swaying tooth group, the value of the resin crown tends to be slightly larger than other prostheses, A significant difference was observed for the hard metal crown.
Further, as can be seen from FIG. 7, the waveform was broken in the metal crown and a high frequency component was contained, and this tendency was often observed especially in the rocking tooth group. In any case, the difference in the prosthesis was not significantly different in the first wavelength except for the rocking tooth mounted with a resin crown having low hardness.

(Effect) Since an acceleration pickup is used, it responds too sensitively in the past and accurately grasps information generated by hammering a tooth due to various factors other than shaking (eg pickup weight, treatment condition of crown). What I did not get was a microphone as a means to catch the hammering sound of the tooth, and by incorporating this microphone in the head of the hammer, the hammering sound was sampled aurally and the vibration waveform of the tooth was clarified on the CRT. There is an advantage that you can draw it. Metal hammer has a wide frequency range and a short duration (0 to 7KH).
z, 0.20 msec), but in the second invention, since the head of the hammer for hammering the teeth is made of synthetic resin, it is the reverse of the metal hammer, and (0-2KHz, 0.57mse
c) It sufficiently covers the resonance point of the tooth, the impact duration is long, and the acoustic response (49.50) of the tooth is sufficient, and the high frequency of the metal itself is added to the vibration waveform due to hammer impact as in the case of metal. There is an advantage that a clean waveform that is easy to see can be obtained without causing the waveform to be broken due to the weight of the components.

[Brief description of drawings]

FIG. 1 ... Block circuit diagram of one embodiment of the present invention FIG. 2 ... Front view of one embodiment of a hammer used in the present invention, FIGS. 3 (a)-(d) ... POM hammer for accelerometer and microphone And a graph showing a vibration waveform drawn on a CRT when used for a metal hammer respectively. FIG. 4 (a) (b) ... Graph showing the relationship between the material and weight of the hammer. FIG. 5: A graph showing the influence of the thickness of the artificial periodontal ligament. FIG. 6 is a graph showing the relationship with the resorption of the marginal alveolar bone of the tooth root. FIG. 7 (a) to (d) ... Vibration waveform graphs drawn on a CRT showing effects of various prostheses on sound teeth and oscillating teeth. FIG. 8 is a graph showing effects of various prostheses on healthy teeth and swaying teeth. (1) ... Microphone, (2) ... hammer, (2a) ... head (3) ... A / D converter, (4) ... storage device (5) ... main controller, (6) ... CRT controller (7) … CRT.

Claims (5)

[Claims] 1. A microphone for catching a hammering sound of a tooth in a tooth mobility measuring device in which a vibration waveform generated by hammering a tooth is caught and drawn on a CRT as a visible vibration waveform. A hammer for measuring tooth mobility, which is characterized by being incorporated in the head of the hammer. 2. The hammer for measuring tooth mobility according to claim 1, wherein the head of the hammer is made of synthetic resin. 3. The hammer for measuring tooth mobility according to claim 2, wherein the synthetic resin is a polyoxymethylene resin. 4. The tooth mobility measurement according to any one of claims 1 to 3, wherein the hammer is provided with an acceptance display indicating that the hammering strength is within a predetermined range. For hammer. 5. The hammer for measuring tooth mobility according to any one of claims 1 to 4, wherein the weight of the hammer is 40 g to 52 g.