JPH0871092A - Initial dental caries detector - Google Patents

Abstract

PURPOSE: To provide an initial dental caries detector capable of simply and accurately detecting initial dental caries within a short time without exerting harmful effect on a human body, capable of expecting the promotion of various measures related to the prevention of dental caries in a form giving satisfactory results and capable of contributing to the reduction of a risk losing a tooth. CONSTITUTION: An initial dental caries detector is equipped with an infrared absorption detection part 3, an illumination optical fiber 4 guiding infrared rays to a tooth 6 to be examined from an infrared transmission part 1 to irradiate the same with infrared rays and a light detecting optical fiber 5 detecting infrared rays reflected from the tooth 6 to be examined to guide the same to the infrared absorption detection part 3. Further, an operation part 8 operating the quantity of infrared rays absorbed by the tooth 6 to be examined from the quantity of infrared rays detected by the infrared absorption detection part 3 and operating moisture content from the quantity of absorbed infrared rays is provided and the degree of initial dental caries is detected from the moisture content.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an initial caries detecting device which can detect an initial caries whose degree of decalcification cannot be confirmed from the outside accurately in a short time, accurately, safely and hygienically. .

[0002]

2. Description of the Related Art Since about 50% or more of the causes of tooth loss are caused by dental caries, prevention of dental caries is extremely important in preventing tooth loss. . However, caries prevention is generally difficult. One of the reasons for this is that caries generally worsen in a state where decalcification progresses under the surface of the teeth and is invisible to the naked eye, and conservative treatment is already required when subjective symptoms or when detected by the naked eye. The point is that it gets worse.

Therefore, what is important in preventing dental caries is
To detect demineralization under the surface of the tooth at an early stage and take appropriate measures to stop the progress of caries. At such an early stage, even if conservative treatment is needed, caries are small, so
It has the advantage that simple treatment is required (the larger the preservative filling, the higher the risk of secondary caries).

More recently, it has been suggested that the initial dental caries can be restored to the original healthy dentin to some extent by the adaptation of fluoride, and the detection of the early dental caries is more and more effective for the prevention of dental caries or the loss of teeth. It is a valuable technology for

On the other hand, the mainstream of caries detection has conventionally been visual inspection using a deep needle and a dental mirror to visually detect caries accompanied by a substantial defect. It is difficult to objectively evaluate the degree of decalcification with good reproducibility.

[0006] Further, as one of the methods of mechanical examination, there is a method using X-ray.
It is known that even with this method, it is generally difficult to detect early caries. Also, a method of knowing the degree of caries by measuring the electric resistance value of the tooth has been known for a long time, but this method has variations in the value depending on the measurement method such as the measurement site, drying conditions, and measurement time. However, there are still problems in practical use, and it has not been widely spread.

Regarding the method of detecting initial caries, recently, in addition to these mechanical detection methods, various methods as shown below have begun to be tried (BA Mansso).
n, J. J. ten Bosch: Advances
in Methods for Diagnostic
Coronal Carriers-A Review,
Advance in Dental Research
h 7 (2): 70: 79, 1993). (A) A method of irradiating a tooth with strong visible light and using the difference in light transmission to detect caries as a shadow, (b) Irradiating a tooth with a laser or ultraviolet rays, and emitting fluorescence from the tooth. To distinguish between healthy and demineralized dentin using the difference between
(C) Since the surface of the demineralized tooth substance is observed to be white, a method of distinguishing between the healthy tooth substance and the demineralized tooth substance by a light scattering method, (d) the tooth is impregnated with a pigment, A method of distinguishing between healthy and demineralized dentin by using the difference in porosity, that is, the difference in staining degree, (e) Difference in mineral density and ultrasonic waves between healthy and demineralized dentin A method of distinguishing between the two by utilizing the difference in the propagation characteristics of.

Each of these methods has advantages and disadvantages, and there are practical possibilities in the future, but there are still considerable problems to be solved. The problems and issues are listed below in response to the above-mentioned example. (B) It is said that the initial caries are large enough to reach the dentin, and the caries are limited to the adjacent caries. (B) A large device is required for laser or ultraviolet irradiation or fluorescence detection, and fluorescence may be emitted from other than demineralized dentin (for example, dysplastic dentin). Has become. (C) In addition to demineralized dentine, malformed teeth that become white or occlusal surfaces with large irregular reflections are maladaptive. (D) The stability or safety of the dye used and its solvent must be ensured. (E) In the case of a relatively small initial caries, this cannot be detected, and in an occlusal surface having a complicated surface, noise is too large and a diagnostic error may occur, and it is difficult to downsize the device. .

In Japanese Unexamined Patent Publication (Kokai) No. 5-337142, a tooth is irradiated with a light beam having a specific wavelength to excite the tooth component, and the emitted light emitted from the excited substance is measured to determine whether the tooth is a healthy tooth or a carious tooth. Discloses that emitted light has different spectra and the difference is used to detect carious teeth.
In this case, the excitation wavelength (irradiation light) is 360 μm to 580
μm, which measures the emitted light with a wavelength of 620 μm or more through a filter.
And has the same problem.

Therefore, it is desired to develop a simple and accurate detection method and detection device for initial caries.

The present invention has been made in view of the above circumstances.
An object of the present invention is to provide an initial caries detecting device capable of detecting an initial caries easily, accurately in a short time, safely, and hygienically.

[0012]

In order to achieve the above object, the present inventor has an infrared transmitter, an infrared absorption detector,
An irradiation optical fiber that guides infrared rays from the infrared transmitter to the test tooth and irradiates the test tooth with infrared light, and a light receiving optical fiber that receives the infrared light reflected by the test tooth and guides it to the infrared absorption detection section, The infrared absorption amount detected by the infrared absorption detection unit calculates the amount of infrared rays absorbed by the test tooth, and a calculation unit for calculating the amount of water from the amount of absorbed infrared rays is provided. Provided is an initial caries detecting device characterized by detecting the degree. In this case, it is preferable that the apparatus further comprises an infrared transmitting substance interposed between the irradiation and receiving optical fibers and the test tooth.

[0013]

That is, the present inventor has conducted extensive studies in order to achieve the above object, and as a result, measured the amount of water present in the decalcified portion of initial caries by utilizing the specific absorption of water in the infrared region. By doing so, the initial caries can be detected simply and quickly, safely and hygienically. Furthermore, in order to detect the initial caries by the above detection method, infrared rays are guided to the oral cavity after irradiation and after absorption. Using a moisture measuring device utilizing infrared rays, which is equipped with a light receiving optical fiber for guiding the infrared ray to a detector, and preferably an infrared ray permeable substance is provided between the irradiation and light receiving optical fibers and the surface of the measurement site. It has been found that intervening is effective.

In this case, in order to improve the detection accuracy of the initial caries, it is necessary to safely detect the change corresponding to the loss of minerals and to apply it to the human oral cavity. That is, 2-3% for healthy enamel
There is 1 to 2% of water in the void, but at the decalcification site in the initial caries state, the mineral disappears and the void content increases. Water will occupy the voids, and depending on the degree of decalcification, water content of several tens% or more will be contained.

In such a state, the present invention quantitatively measures the increased water content (corresponding to the lost mineral content) at the decalcification site of the initial caries lost by decalcification.
The moisture content and the loss of minerals are highly compatible and accurate, and since caries can be detected non-destructively and in a non-contact manner by infrared rays, it is safer to the human body and hygienic than other existing methods. It is advantageous, and detection on the occlusal surface where the frequency of initial caries is high is possible.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1. In the figure, 1 is an infrared ray transmitting section (light source), 2 is an infrared spectroscopic section (monochromator), 3 is an infrared absorption detecting section ( Sensor), an optical fiber 4 for irradiation is connected to the spectroscopic section 2, and an optical fiber 5 for receiving light is connected to the detecting section 3, which is transmitted by the transmitting section 1 and predetermined by the spectroscopic section 2. The infrared ray adjusted to the wavelength of is guided to the irradiation optical fiber 4 and irradiated to the test tooth 6 from its tip, and the infrared ray reflected by the test tooth 6 is received by the light receiving optical fiber 5 and is detected by the detection unit 3. It is supposed to be guided.

Here, the infrared wavelength region may be any wavelength as long as it is a wavelength that is less affected by infrared absorption by tooth components, but a wavelength of 0.7 μm or more and 100 μm or less is preferable, for example, in the near infrared region. At the wavelength of 1.2 μm,
1.46 μm, 1.96 μm and 2.95 μm can be used.

As the above-mentioned optical fibers, it is necessary to install an irradiation optical fiber for guiding infrared rays into the oral cavity and a light receiving optical fiber for guiding infrared rays absorbed by the test tooth to the detector. Separated from each other,
Alternatively, it may be a single fiber cable in which the irradiation and the reception are integrated. In the narrow oral cavity, the integrated one is better in usability. Further, the thickness of this cable is smaller than the size of the teeth, and is preferably 1 mm or more in order to secure a sufficient amount of light. Also,
The cable must always be used hygienically, and from a practical point of view, at least the part that comes into contact with the oral environment can be disinfected (chemical resistance to disinfectant, heat resistance to heat sterilization operation). Preferably there is.

Further, in the figure, 7 is an amplification unit, 8 is an absorption intensity calculation unit (converter), and 9 is an absorption intensity output unit (display of measurement results).
The infrared absorption detection amount detected by the detection unit 3 is amplified by the amplification unit 7, the infrared amount absorbed by the test tooth 6 is calculated from this value by the calculation unit 8, and the moisture amount is calculated from this. The result is output from the output unit 9.

When measuring the degree of initial caries using the above-mentioned device, the tips of the irradiation and reception optical fibers 4 and 5 are opposed to the test tooth 6, and the light is transmitted from the transmitter 1 and the spectroscope 2 is used. The test tooth 6 is irradiated with infrared rays adjusted to a predetermined wavelength. As a result, part of the infrared rays is absorbed by the moisture in the test tooth 6, and the infrared rays that are not absorbed are reflected. The light-receiving optical fiber 5 receives the reflected infrared ray and transmits it to the detecting section 3, and the calculating section 8 calculates the infrared ray amount absorbed by the test tooth 6, that is, the water content, and the output section 9 The result is output.

Here, in the initial caries targeted by the present invention, the tooth surface seems to be kept almost healthy, but decalcification is observed under the surface of the tooth, or there is a large substantial defect. However, it is caries with small caries. Clinically, it is a demineralized dentin corresponding to C ₀ to C ₁ levels.

Further, in the measurement, since only the water present inside the initial caries is correctly measured, excess water (eg saliva, plaque, etc.) on the tooth surface corresponding to the measurement site is measured.
Stain should be thoroughly removed in order to eliminate the interference between light and the foreign matter on the tooth surface, which is derived from food residue). On the contrary, excessive drying of the measurement area should be avoided.

Furthermore, in order to suppress the output (irradiation) on the surface of the moisture measuring portion and the diffuse reflection of the input infrared rays, the above-mentioned detecting device is provided with both fibers 4, 5 and the surface of the test tooth 6 as shown in FIG. It is effective to interpose the infrared permeable substance 10 between them. As the infrared permeable substance, a water-insoluble soft solid or viscous liquid is preferable in order to secure the adhesion and the holding property to the surface of the test tooth 6, and specifically, Nujol, hexachlorodiethane, and silicone. oil,
Mineral oil, vegetable oil, etc. are illustrated.

Next, a concrete example of the initial caries detection of the present invention will be shown by an experimental example. [Experimental example] Preparation of initial caries sample for moisture measurement: To reduce the variation between samples for measurement and to grasp the correlation between the degree of initial caries demineralization and the water content, the degree of decalcification Created a known model of initial caries. That is, the enamel of the bovine anterior tooth was removed from the demineralization window of about 5 mm square, and the other enamel surface was covered with manikin. By decalcifying this with a lactate buffer (0.1 M, pH 4.3) for a certain period (3 days to 2 weeks), subsurface decalcification nests with different degrees were obtained, and this was used as an initial sample for moisture measurement. It was used as a corrosion sample. Moisture measurement of initial caries sample: Each of the above samples was immersed in distilled water for a sufficiently long time, taken out, and excess water remaining on the surface of the sample was wiped off. Next, by irradiating infrared rays at a right angle to the window portion of this sample using the moisture measuring device having the configuration shown in FIG. 1 and detecting the amount of light returning from the window portion, it is contained in the subsurface decalcification nest. The water content was measured. The results are shown in Figure 2. Infrared irradiation conditions: Water content was measured under the following conditions. That is, light having a wavelength of 1960 nm is irradiated from the direction perpendicular to the irradiation surface (the surface of the demineralized sample containing water) and 10 mm
Irradiated at a distance of. The area irradiated at this time was circular with a diameter of 11 mm.

From the results shown in FIG. 2, the amount of water (moisture meter) contained in the initial caries lesion (model lesion on the bovine tooth) was determined according to the degree of decalcification of the initial caries (in this case, the number of decalcification days). It was confirmed that the initial caries can be detected by measuring the infrared absorption of water.

[0026]

The initial caries detecting device of the present invention is capable of simply and accurately detecting initial caries, which has hitherto been difficult, without adversely affecting the human body. , Therefore, the preventive effect of caries preventive agents can be objectively evaluated, and various measures related to caries prevention can be expected to be promoted in a more effective manner, resulting in a risk of tooth loss. It can also contribute to mitigation.

[Brief description of drawings]

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

FIG. 2 is a graph showing the results of measuring the water content of the initial caries sample in the experimental example.

[Explanation of symbols]

 1 Infrared emission part (light source) 2 Infrared spectroscopic part (monochromator) 3 Infrared absorption detection part (sensor) 4 Optical fiber for irradiation 5 Optical fiber for receiving light 6 Test tooth 7 Amplification part 8 Absorption intensity calculation part 9 Absorption intensity output part 10 Infrared transmission Sexual substance

Claims (2)

[Claims] 1. An infrared transmitter (1), an infrared absorption detector (3), and infrared rays from the infrared transmitter (1) are guided to a test tooth (6) to irradiate the test tooth (6) with infrared light. An irradiation optical fiber (4), an optical fiber (5) for receiving the infrared light reflected by the test tooth (6) and guiding it to the infrared absorption detecting section (3), and the infrared absorption detecting section (3). An infrared ray amount absorbed by the test tooth (6) is calculated from the infrared ray amount detected in step 1, and a calculation part (8) that calculates the moisture amount from the absorbed infrared ray amount is provided. An initial caries detection device characterized by detecting the degree of caries. 2. The device according to claim 1, further comprising an infrared transmitting substance (10) interposed between the irradiation and receiving optical fibers (4, 5) and the test tooth (6).