JPH11160264A - Detector for pore or crack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detector by which the porosity of an object or the degree of a crack is detected precisely, simply and nondestructively. SOLUTION: A detector for a pore or a crack is provided with an infrared camera 1 which senses radiant infrared rays from an object 2 and with an image processor 3 by which an electric signal, by the radiant infrared rays, generated by the camera 1 is changed into a thermal image. The detector is provided with a means by which the surface of the object 2 is kept at a prescribed temperature and by which the pore or the crack in the object 2 is impregnated with a volatile liquid without forming the film of the liquid on the surface of the object 2, with a means by which the pore or the crack in the object 2 is covered so as to prevent the volatile liquid from being gasified from the pore or the crack and with one or two or more means by which the volatile liquid existing in a recessed part is removed when the surface of the object 2 is uneven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pore or crack detecting device for non-destructively detecting the porosity of a substance having pores or fine cracks on the outer surface or the degree of a crack gap. Dental caries, depth and extent of pits and fissures on the occlusal surface of the molars, gaps in the filling of the dentin, oral areas such as cracks in the dental filling, and fine cracks on the outer walls of the cement and glass Detecting and evaluating the porosity of various objects and the degree of cracking, such as controlling the moisture content of wood, evaluating the clogging of filtration filters, evaluating the degree of drying of cloth and cotton, and identifying the location of water leaks in water pipes. An effective detection device.

[0002]

2. Description of the Related Art There are various conventional devices for non-destructively detecting the porosity of a substance having pores or fine cracks on its outer surface or the degree of crack gaps. There are suggestions. In particular, as a method and an apparatus for detecting and diagnosing initial caries, there are proposals as described in the prior art of Japanese Patent Application Laid-Open No. 8-233758, but each has problems and is not practical.

[0003] The present applicant has disclosed in Japanese Patent Application Laid-Open No. Hei 8-2337.
No. 58, "An infrared camera that senses radiant infrared rays from the test teeth, an image processing apparatus that thermally images electrical signals due to the radiant infrared rays generated by the infrared camera, a television monitor that displays the thermal images, and An initial caries detection device comprising one or both of a recording reproduction device that electromagnetically records and reproduces the thermal image described above. "

[0004] This apparatus can detect the initial caries easily and accurately in a short time, and furthermore, safely and hygienically. It was desired to detect it properly, especially to detect milder initial caries more reliably.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to meet the above-mentioned demands, and non-destructively measures the degree of porosity or the degree of cracks in an object having pores or fine cracks on its outer surface. An apparatus for detecting, an infrared camera for sensing radiant infrared rays from the object, an image processing apparatus for converting an electric signal by the radiant infrared rays generated by the infrared camera into a thermal image or digital information, and the image processing apparatus And (A) a computer that drives a computer, a television monitor that displays the thermal image or digital information, and / or a recording / reproducing device that electromagnetically records / reproduces the thermal image or digital information. Means for maintaining the surface of the object at a predetermined temperature and impregnating the pores or cracks of the object with a volatile liquid without forming a film of the liquid on the surface of the object; (B) Means for covering the pores or cracks of the object to prevent the volatile liquid from evaporating from the pores or cracks; and (C) removing the volatile liquid present in the recesses when the object surface is uneven. A pore or crack detection device provided with any one of the means or two or more means.

[0006] This detection device is disclosed in Japanese Patent Application Laid-Open No. Hei 8-2337.
By improving the prior invention of JP-A-58-58, it is possible to more easily and accurately detect and evaluate pores and fine cracks in an object such as initial caries.

That is, the initial caries detecting device of the prior invention is based on the following findings. 2-3 for healthy enamel
% Of voids, which contain 1 to 2% of water. However, in the demineralized part in the initial caries state, minerals disappear and the degree of porosity increases. The voids are occupied by water, and depending on the degree of demineralization, about 10% or more of water is contained. The increased water content (corresponding to the lost minerals) means that the thermal difference between healthy and demineralized dentin has increased. That is,
The more moisture present in the initial caries site, the greater the difference in thermal behavior with surrounding healthy sites. In order to measure this thermal difference quantitatively, non-destructively and non-contactly, we focused on infrared thermal energy. Generally, the following relationship exists between infrared thermal energy and the radiation temperature from it. By measuring infrared thermal energy that is present, the temperature of the inspection site can be known. The prior invention and the present invention use the temperature difference as a means for detecting initial caries.

W = a × b × T (W is infrared thermal energy, T is the absolute temperature of a substance (sample), a is emissivity (≦ 1), and b is Stefan-Boltzmann constant.)

In the prior invention, it has been found that it is more effective to provide a means capable of enhancing a thermal difference between a healthy tooth substance and a tooth substance in an initial caries state. As described above, in the prior invention, the change in proportion to the loss of minerals is measured by using the above-described method to measure the difference in thermal behavior from the healthy part based on the amount of water present in the demineralized part of the initial caries. Can be caught correctly,
The present invention provides a technology that can detect initial caries easily, in a short time, and safely and hygienically.

However, in order to reliably detect lighter initial caries, further technical improvements were required. In the present invention, the basic principle and the basic device relating to the detection / diagnosis of the initial caries are the same as those of the prior invention. The present invention is more practically improved by adding any one or more of the means (A) to (C).

More specifically, the features of the means (A) to (C) will be described in detail by taking an example of a method for detecting initial caries. The means (A) maintains the temperature of the surface of a test tooth at a predetermined temperature. ,
In addition, it is a means for containing moisture without forming a water film on the surface of the test tooth.When the surface temperature of the test tooth is set to be constant at an arbitrary temperature before moisture vaporization, the water is simultaneously poured inside the tooth. It is a means to supply without shortage. If the water supply is insufficient, judge the degree of demineralization slightly less than actual,
On the other hand, when excess water is left to form a water film on the surface of the test tooth, the degree of demineralization is determined to be more serious than it actually is. By this means, such a misdiagnosis trouble can be avoided, and at the same time, the measurement conditions before and after the operation can be set to be the same.From the comparison of the thermal images before and after the operation, whether the decalcification site has progressed further Alternatively, it can be easily determined whether remineralization has been repaired.

Next, as the means (B), for example, a transparent and flexible thin film agent which is in close contact with the surface of the test tooth and prevents vaporization of moisture from the surface of the test tooth can be used. This is when the demineralized area is spread over a wide area, or when the demineralized part and the healthy part are anatomically heterogeneous parts, that is, it is virtually impossible to compare the demineralized part and the healthy part on the thermal image Adopted in the case. In such a case, after a sufficient amount of water is supplied to the surface of the test tooth, first, the thin film is brought into close contact with the decalcified tooth surface, and the temperature drop on the thin film is measured by an infrared camera. This data is adopted as temperature data at a healthy part. Next, the thin film is removed, and the same portion (decalcified tooth surface) is similarly subjected to temperature measurement. This data is adopted as temperature data at the demineralization site. By comparing the two data, it is possible to accurately measure the temperature drop due to the vaporization of the water contained in the demineralized nest. In a healthy part, since the evaporation of water is extremely small, the difference in the temperature drop due to the presence or absence of the thin film is small, and is not a problem.

The means (C) is used, for example, when the test tooth is an occlusal surface, and a water absorbing sheet is used.
This is used to distinguish between healthy pit fissures that have not been demineralized and those that have been demineralized. That is, usually, when the pit fissure is deep, the moisture remaining there cannot be easily removed. Therefore, the water absorption sheet absorbs excess water in the pit and fissure, and in the case of a healthy pit and fissure, the temperature drop due to air blowing is small, similar to the degree of temperature drop on a smooth surface. On the other hand, in the case of the demineralized pit and fissure site, the temperature drop was immediately recognized by the blast, and the duration was clearly longer, and the degree of the temperature drop and the duration corresponded to the degree of demineralization. Is what it is.

In the present invention, a means for observing the pores or cracks may be further provided. This is an auxiliary device when the test tooth observes the occlusal surface, the adjacent surface, the buccal side / lingual side of the back teeth, etc., and is used to make the observed tooth surface easier to see. Specifically, a gold mirror that totally reflects infrared rays can be employed. That is, the gold mirror is moved 4
By placing the camera at an angle of 5 degrees and capturing the reflected infrared light from the front with an infrared camera, it is possible to easily observe the initial caries present in the above-mentioned difficult-to-observe parts.

In the present invention, there can be provided a means for enhancing the thermal difference between the pores on the surface or the portion thereof and the surrounding portions as in the prior invention.

The apparatus of the present invention can be effectively used for detecting the depth and width of pits and fissures in the initial caries and posterior occlusal surfaces, the pores of oral objects such as dental fillings, and cracks. It can be suitably used for detecting pores and cracks in various other objects, and the means (A), (B) and (C) provide the same features as described above.

That is, the present invention relates to information on the temperature drop (heat) which is observed when a volatile liquid such as water penetrates into an object having a pore structure or fine cracks in the outer layer in contact with the atmosphere and the liquid is vaporized. It provides a technique for estimating the pore structure of the object or the state of minute cracks from the image or digital information), and usually observes a decrease in temperature due to vaporization of water (here, free water). At present, information on temperature drop can be detected even with slight temperature changes due to the development of a high-sensitivity infrared camera,
In particular, when such a pore structure or minute cracks cannot be easily detected from the outside, and when it is necessary to detect the state of the pores or cracks nondestructively and simply, The invention is valid. For example, as described above, it is effectively used for detection of initial caries in a state of subsurface demineralization before reaching the cavity, and if such initial caries can be appropriately detected / diagnosed, Early detection / early measures are possible. As a result, the caries to be treated are almost in their infancy, the treatment is much simpler than it is now, and the damage to the teeth is small. However, in addition to the above, the present invention also discloses the detection of fine cracks in the outer wall of cement and glass, the evaluation of the dryness of wood, the evaluation of the degree of clogging of a filter, the evaluation of the degree of dryness of cloth and cotton, If the abnormality you want to inspect is very small, such as identifying the location of water leaks, which is difficult to detect with the naked eye, if it is difficult to observe the internal state, or if you want to inspect the object nondestructively, This is effective when it is difficult to find an abnormality under normal conditions, such as when the brightness cannot be secured (the infrared camera does not depend on visible light), or when the target cannot be sufficiently approached due to danger or the like.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an apparatus for detecting an initial caries. In the figure, reference numeral 1 denotes an infrared camera for detecting radiated infrared rays from a test tooth 2, and 3 denotes an electric signal generated by the radiated infrared rays generated by the infrared camera 1. An image processing apparatus 4 for converting the image into a thermal image or digital information is a computer for driving the image processing apparatus 3.
Reference numeral 5 denotes a television monitor for displaying the thermal image or digital information, and reference numeral 6 denotes a recording / reproducing apparatus for electromagnetically recording / reproducing the thermal image or digital information. Note that an optical fiber cable 1a extending to the test tooth 2 may be attached to the infrared detection end of the camera 1 in order to (semi-) quantitatively detect the degree of initial caries, which is a relatively small object. The thickness of this cable is smaller than the size of the teeth,
Moreover, in order to secure a sufficient amount of light, 1 mm or more is preferable.

Reference numeral 7 denotes a means for blowing dry air at a predetermined temperature to the test teeth and a means for dropping or penetrating a liquid at a predetermined temperature to the test teeth between the initial caries site and surrounding healthy tooth material. It is a means to emphasize the thermal difference.

FIG. 2 shows that the surface of the object (test tooth) is maintained at a predetermined temperature and the pores or cracks of the object are impregnated with a volatile liquid such as water without forming a film of the liquid on the surface of the object. An example of the means (volatile liquid impregnating means) 10 is shown. In this example, a sponge-like water retention / flexible cylinder 12 is attached to the tip of a columnar constant temperature heating element 11 made of ceramics or the like. To which a heating wire 13 is attached. This means 10 heats the heating element 11 to a fixed temperature (a range of 28 to 32 ° C. is appropriate) by means of a heating wire 13, and makes the sponge-shaped tube 12 contain moisture. By contacting the initial carious site 2a, the initial carious site (pores or cracks) 2a
Water can be supplied without excess or shortage.

FIG. 3 shows an example of a means (a volatile liquid vaporization preventing means) 20 for covering the pores or cracks of an object (test tooth) and preventing the vaporization of volatile liquid such as moisture from the pores or cracks. As the means 20, a sheet or film having a property of being transparent and flexible and easily adhering to the tooth surface is used. Specifically, a commercially available transparent sheet for cooking (wrap film of polyvinylidene chloride or the like), a spreadable parafilm (trade name), or the like can be used, and the test tooth 2 covers the initial carious site 2a. It is something that is brought into close contact.

FIG. 3 shows that when the surface of the object (test tooth) is uneven, for example, when the test tooth is an occlusal surface, volatile liquid such as water present in the concave portion (for example, remains in the pit and fissure of the occlusal surface) This shows an example of the means (volatile liquid removing means) 30 for removing the excess water 2b). As the means 30, a flexible water absorbing sheet or the like can be used. Any water-absorbing sheet may be used as long as it has flexibility and water absorption, and a cellulosic sponge sheet,
A non-woven cotton sheet or the like can be used.

In the present invention, in the apparatus as shown in FIG. 1, the means 10, 20, 30 shown in FIGS.
Or any one of the above means.

When detecting the initial caries using the above-mentioned apparatus, the radiant infrared rays of the test teeth are sensed by the camera 1 via the cable, and this is image-analyzed by the image processing apparatus 3 and the result is represented as a temperature distribution. The image is projected on the television monitor 5 as an image. In this case, before the measurement, water is supplied to the pores or cracks of the test tooth without excess or shortage by the means of FIG. Can be reliably detected, and a misdiagnosis trouble can be avoided.
When the test tooth is an occlusal surface, the water 2b remaining in the pit and fissure is removed by the means 30 shown in FIG.
This makes it possible to distinguish between healthy pit fissures that have not been demineralized and pit fissures that have been demineralized, and to correctly determine the presence or degree of demineralization of the demineralized pit fissures.

In the above measurement, it is difficult to compare the demineralized part with the healthy part, for example, when the demineralized part of the test tooth is extensive or when the demineralized part and the healthy part are anatomically heterogeneous parts. Means (transparent and flexible thin film agent)
This is applied to a test tooth, and the above measurement is performed in this state. Then, the thin film agent is peeled off, the same measurement is performed, and both data are compared. Here, the former data is adopted as the data of the healthy part and the latter data is adopted as the data of the demineralized part, whereby the degree of demineralization of the test tooth can be accurately measured. In this case, it is a matter of course that the means shown in FIGS.

In the measurement, if the test tooth is a hardly observable part such as an occlusal surface or an adjacent surface, or a cheek side or a lingual side of a back tooth, the surface of the mirror of the dental mirror is gold-plated to totally reflect infrared rays. By using an auxiliary device such as a mirror, for example, a gold mirror can be arranged at an angle of 45 degrees with respect to the observation tooth surface, so that infrared light totally reflected can be captured from the front by an infrared camera.

Further, in the above measurement, similarly to the above-mentioned prior art, a constant temperature of dry air is blown to promote the vaporization of water, to measure the lowered tooth surface temperature, or to remove volatile liquid such as ethanol. After applying and gently wiping off excess liquid, a method of measuring the surface temperature of the teeth due to natural vaporization of the liquid may be adopted.In the former case, the conditions for blowing air to the tooth surface in the present invention are as follows: The range is practically appropriate. That is, the spraying distance is 10 to 30 cm
Is appropriate. If it is shorter than this, it is too close to the patient's face, and there is a problem in operability and feeling of pressure on the patient. If it is longer than this, it is difficult to apply air to a predetermined part. The spray pressure is suitably 3 to 20 liters per minute. If it is smaller than this, sufficient vaporization does not take place, making measurement difficult, and if it is larger than this, the patient suffers from pain and noise in terms of teeth and gums. The diameter of the spray tube is 1mm ~ 2
cm is appropriate. If it is smaller than this, a sufficient amount of air cannot be obtained, and it is difficult to measure the temperature drop. If it is larger than this, it is difficult to apply air to a predetermined site, and furthermore, the lips and nose are hit by wind and discomfort is felt. The air blowing temperature is suitably from 20 to 40 ° C. If it is lower than this, pain is felt in the teeth, and if it is higher than this, moisture vaporization is too fast in less than 10 seconds, and the reproducibility of temperature measurement is reduced. When measuring, the surface temperature of the tooth is suitably from 25 to 35 ° C. If the measurement is performed at a lower temperature, the degree of temperature decrease is small, and the difference from a healthy part is small. To measure the temperature drop at a higher temperature, the measurement must be started immediately after opening the mouth, and the reproducibility of the temperature measurement is reduced. The blowing time of the air is within a maximum of 5 minutes in consideration of the burden on the patient.

Next, the effects of the present invention will be specifically described with reference to experimental examples.

[Experimental Example] Using the apparatus shown in FIG. 1, an experiment was conducted by the following method. Prepare a human extracted tooth having an initial caries (white spot) without cavities on the smooth or occlusal surface of the molar tooth as a measurement sample, and immerse it in a container containing distilled water at 37 ° C for a sufficient time in advance. Oita. Next, when measuring the temperature of the demineralized area using an infrared camera, remove the sample from distilled water, fix it so that only its root is immersed below the water surface, and lighten the excess moisture adhering to the tooth surface I wiped it off. After that, spray dry air at a certain temperature to promote the evaporation of water, measure the lowered tooth surface temperature, or apply a volatile liquid such as ethanol, and gently wipe off the excess liquid, A method for measuring a decrease in tooth surface temperature due to natural vaporization of the liquid was implemented, and the following means A, B, C or D were adopted and compared with the method. Means A: a rod-shaped dental water-absorbent roll cotton is made to contain moisture,
This is maintained at a constant temperature of 28 to 32 ° C. with a heating wire, pressed against the measurement site of the sample for about 20 seconds, and the pores at the measurement site are held with an amount of water corresponding to the pores.
The above measurements were made. Means B: A cooking wrap film made of polyvinylidene chloride is closely attached to a measurement site of the sample, and after performing the above measurement, the wrap film is peeled off, and the above measurement is similarly performed.
The former and the latter were compared. Means C: When measuring the occlusal surface of the molar, after removing the water in the pit and fissure by pressing a cellulosic sponge sheet,
The above measurements were made. Means D: A gold mirror having a mirror-finished surface of a dental mirror was used, and the infrared light reflected there was captured by an infrared camera. Result [A] By adopting the means A, in comparison with the method,
(1) The initial temperature of the tooth surface is always constant, and highly reproducible data on temperature information such as thermal images can be obtained. (2) The degree of progress of demineralization or remineralization of one tooth can be clearly compared. (3) The excess moisture can be easily wiped off, and the operability has been improved. [B] By adopting the means B, in contrast to the method,
(1) The degree of temperature decrease when a thin film is brought into close contact with the demineralized tooth surface can be regarded as a control surface (non-demineralized healthy tooth surface) with respect to the demineralized tooth surface, and the temperature difference from the case where the thin film is not adhered. By comparing the results, the degree of demineralization in each individual tooth could be estimated. [C] By adopting the means C, in contrast to the method,
(1) The erroneous distinction between a healthy occlusal surface and a demineralized occlusal surface is reduced. (2) The difference in the temperature drop pattern between the healthy occlusal surface and the demineralized occlusal surface became clear. [D] By adopting the means D, in contrast to the method,
(1) Observable parts, such as the back teeth and the cheek / lower side, became easier to observe. (2) Workability was improved, and the time required for temperature measurement could be shortened.

[0030]

According to the present invention, the porosity and the degree of cracks of an object can be detected accurately, easily and nondestructively.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing an example of a volatile liquid impregnating means.

FIG. 3 is a schematic perspective view showing an example of a volatile liquid vaporization preventing means.

FIG. 4 is a schematic sectional view showing an example of a volatile liquid removing means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Infrared camera 2 Test tooth 2a Initial caries part 2b Water remaining in pit and fissure 3 Image processing device 4 Computer 5 TV monitor 6 Record reproduction means 7 Thermal difference emphasis means 10 Volatile liquid impregnation means 20 Volatile liquid vaporization prevention Means 30 Volatile liquid removal means

Claims (4)

[Claims] An apparatus for non-destructively detecting a porosity or a degree of a crack in an object having pores or fine cracks on an outer surface thereof, comprising: an infrared camera for detecting radiant infrared rays from the object; An image processing device for converting the electric signal generated by the infrared camera by the radiant infrared rays into a thermal image or digital information; a computer for driving the image processing device; a television monitor for displaying the thermal image or digital information; A recording / reproducing device for electromagnetically recording / reproducing an image or digital information; and (A) maintaining the surface of the object at a predetermined temperature and volatile in pores or cracks of the object. Means for impregnating a liquid on the surface of the object without forming a film of the liquid, (B) a volatile liquid covering the pores or cracks of the object and covering the pores or cracks of the object. A means for preventing vaporization, and (C) means for removing volatile liquid present in the concave portion when the surface of the object is uneven, or two or more means. Pore or crack detection device. 2. The apparatus according to claim 1, further comprising auxiliary means for observing pores or cracks on the surface of the object. 3. The apparatus according to claim 1, further comprising means for enhancing a thermal difference between a pore or a crack site on the surface of the object and a site therearound. 4. The method according to claim 1, wherein the object is an intraoral object.
4. The device according to 2 or 3.