JP2001087223A - Method and device for observing gingiva - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp the inflammation condition of the gingiva quantitatively with an acute sensitivity. SOLUTION: At least either S-polarized light or P-polarized light is irradiated on the surface of the gingiva. The S-polarization component or the P- polarization component of the reflected light when S-polarized light is irradiated, or the S-polarization component or the P-polarization component of the reflected light when P-polarized light is irradiated is received independently, and based on the intensity of the received light, the surface reflected light component or the inner reflected light component when the natural light is irradiated on the gingiva is found independently. The gingiva is observed by obtaining a surface reflected light image or an inner reflected light image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of observing gingiva by extracting surface reflected light or internal reflected light of gingiva by utilizing the polarization characteristics of light and performing colorimetric analysis of the gingiva, and using this method. The present invention relates to a gingival observation device.

[0002]

2. Description of the Related Art As a method for dentists and dental hygienists to grasp the state of periodontal disease such as gingivitis and periodontitis, subjective evaluation index (gingival index (GI), papillar
y gingivitis-marginal gingivitis-attached gingivit
is (PMA-index), periodontal score (PS), etc. are known, redness and swelling, bleeding,
The index is given based on the presence or absence of ulcers and the presence or absence of chief complaints such as hyperesthesia and itching.

[0003] As a method of objectively grasping the gingival condition, generally, measurement of the pocket depth, measurement of the attachment level, measurement of the degree of alveolar bone resorption by X-ray, bacterial examination, quantification of the amount of gingival crevicular fluid per unit time, It is known to quantify the activity of a specific tissue-destructing enzyme derived from bacteria present in gingival crevicular fluid. On the other hand, gingival color change is considered important in treating periodontal disease because it is useful for diagnosis, treatment, progress, prognosis, etc., and quantifying gingival color to objectively grasp gingival condition Attempts to do so have been researched.

[0004] Methods for objectively evaluating gingival color are broadly classified into a luminous colorimetric method and a photoelectric colorimetric method. What is luminous colorimetry?
This is a method of quantifying the color display of the gingival measurement area by visually selecting the closest color from the standard color chart to the gingival color (Masumi Ibusuki, "About gingival color by luminous colorimetry""Stomatology, 42 , 55 (1975)).

The photoelectric colorimetric method can be further roughly classified into a stimulus value direct reading method and a spectral measurement method. A direct quantification method for quantifying gingiva directly and an indirect quantification method for indirect quantification from photographs, slide films, digital images, etc. have been proposed for each (Kouichi Fukai “Study on gingival color”) Journal of Periodontology, 30 , 428 (1988)).

[0006]

Originally, the criterion of the subjective evaluation index by visual inspection or palpation is based on the degree of redness of the gingiva, but depends on the subjective judgment of the dentist or dental hygienist. Therefore, there is a variation in evaluation among operators due to the skill level and the like. Further, since the determination result is rough, it is not enough to express the state in detail with reproducibility.

[0007] Among the attempts to quantify the color of the gingiva, the luminous colorimetric method is difficult to discriminate with the naked eye due to the large number of color charts, so that the operator needs sufficient color memory training and is reproduced. There is also difficulty in sex. Various reports have been made on the photoelectric colorimetric method. However, in the direct gingival color quantification method, the measurement area of the probe is limited, and it is difficult to measure in a narrow oral cavity, particularly in the gingival part. Furthermore, in the contact measurement using a probe, an anemia band is generated in a gingival where the submucosal connective tissue is thin, so that there is a problem that it is difficult to measure the original gingival color. Even in the indirect quantification method from photographs and digital images, photographs include blurring during development, and digital images include texture information derived from surface irregularities etc. in color tone information inside gingival tissue to be observed. Because they are mixed, quantitative interpretation is difficult.

On the other hand, in addition to the color of the gum, the shape change of the periodontal tissue due to inflammation such as swelling of the gum is also an important criterion for determining the inflammatory state of the periodontal tissue. The objective evaluation method has not yet been put to practical use.

Therefore, in the present invention, in determining the inflammatory state based on the change in color and shape of the gum, the reproducibility is good regardless of the skill of the operator and the gingival state is determined with a sharp sensitivity. The purpose is to be able to be.

[0010]

SUMMARY OF THE INVENTION The present inventors have analyzed the gingival surface reflected light and the internal reflected light to determine the degree of gingival color, swelling, etc. with a sharp sensitivity by analyzing each of the reflected light and the internally reflected light. The present inventors have found that the present invention can be realized, and have completed the present invention.

That is, according to the present invention, the gingival surface is S-polarized
S-polarized component or P-polarized component of reflected light when at least one of polarized light is incident and S-polarized light is incident, or P
Independently receives the S-polarized component or the P-polarized component of the reflected light when polarized light is incident, and based on the received light intensity,
A gingival observation method characterized by independently obtaining a surface reflected light component or an internal reflected light component when natural light is incident on the gingiva and obtaining a surface reflected light image or an internally reflected light image.

As a method of forming a surface reflected light image suitable for analyzing and evaluating the surface condition of the gingiva, a method of forming a surface reflected light image of a gingival surface component, which is a spatial frequency component belonging to an equivalent visual band of a human visual system, is used. A method for forming a surface reflected light image based on the same is provided.

Further, as a method of quantifying the observation result of the gingival surface condition and analyzing and evaluating the gingival surface condition based on the quantified numerical values, a method of analyzing the gingival surface reflected light component of the human visual system is described. Provided is a method for integrating the power of spatial frequency components belonging to the equivalent visual band and evaluating the gingival surface condition based on the integrated value.

Further, the present invention provides an irradiating means comprising an irradiating light source and a polarizing filter, which is capable of independently causing S-polarized light or P-polarized light to enter the gingival surface; A polarizing filter that transmits an S-polarized component or a P-polarized component of reflected light due to polarized light, an imaging device that receives an S-polarized component or a P-polarized component that has passed through the polarizing filter, a surface reflected light image or an interior based on a signal from the imaging device A gingival observation device comprising a control operation device for outputting a reflected light image to a monitor and a monitor.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. In each of the drawings, the same reference numerals represent the same or equivalent components. Also, in the following description, uppercase suffixes D and S in the reference numerals are respectively internally reflected light,
The lowercase letters p and s represent the P-polarized light component and the S-polarized light component of the reflected light, respectively.

The present invention is based on the following principle when S-polarized light and P-polarized light are incident on the gingiva.

As shown in FIG. 1, for example, the gingiva G is passed from the light source 1 through the light source side P-polarizing polarizing filter 2p.
When the polarized light Lp is incident, the reflected light includes the surface reflected light LSp and the internal reflected light LDp, but the surface reflected light generally maintains the polarization of the incident light.
Sp has a P-polarized light component LSpp and is considered not to contain an S-polarized light component. On the other hand, since the internal reflection light LDp loses its polarization, it is considered that the P-polarized light component LDpp and the S-polarized light component LDps contained therein have the same intensity.

Therefore, when the reflected light of the P-polarized light Lp from the gingiva G is observed by the image pickup device 4 through the light-receiving-side P-polarized light polarizing filter 3p, as shown in FIG. The P-polarized light component LSpp constituting the light and the P-polarized light component LDpp of the internally reflected light will be observed.

Here, as the light-receiving-side polarization filter, P
When the polarization filter 3s for S-polarization is used instead of the polarization filter 3p for polarization, as shown in FIG. 3B, only the S-polarization component LDps of the internally reflected light is observed in the image pickup device 4. Become.

The phenomenon in which the component of the reflected light observed by the imaging device 4 when the P-polarized light is incident on the gingiva G differs depending on the type of the polarizing filter on the light receiving side is as follows.
This also occurs when polarized light is incident.

From this, the intensity I (S) of surface reflected light and the intensity I (D) of internal reflected light when natural light is incident on the gingiva G are reflected light when P-polarized light is incident on the gingiva. P
The intensity I (pp) of the polarization component and the intensity I (ps) of the S-polarization component, and the intensity I (sp) of the P-polarization component and the intensity I (S) of the S-polarization component of the reflected light when S-polarization enters the gingiva. ss) can be calculated according to the following equations (1) and (2), respectively (see JP-A-7-75629).

[0022]

I (S) = (I (pp) −I (ps)) + (I (ss) −I (sp)) Equation (1) I (D) = 2 · I (ps) + 2 · I (sp) Equation (2) Further, more simply, the following equation (3), (4) or (5), (6) can be used instead.

[0023]

I (S) = I (pp) −I (ps) Equation (3) I (D) = 2 · I (ps) Equation (4)

[0024]

I (S) = I (ss) −I (sp) Equation (5) I (D) = 2 · I (sp) Equation (6)

Therefore, in the gingival observation method of the present invention, at least one of S-polarized light and P-polarized light, more preferably S-polarized light and P-polarized light, respectively, is incident on the gingival surface, and the S-polarized light component of the reflected light in each case is reflected. And the P-polarized light component, and according to the above equations (1) to (6), more preferably, the equations (1) and (2), the surface reflected light intensity and the internal reflected light when natural light enters the gingiva. The intensities are obtained independently and the surface reflected light image and the internal reflected light image are formed based on them. The surface reflected light image obtained in this way has information on the texture such as unevenness of the gingival surface, and the internal reflected light image has information on the color tone inside the gingival tissue.

Further, in the present invention, it is preferable to analyze the color of the surface reflected light or the internally reflected light. This makes it possible to calculate an inflammation state such as gingival redness as a detailed quantitative value from, for example, internal gingival reflected light, and to quantify an inflammatory state such as edema or swelling of the gingiva from gingival surface reflected light. Becomes possible. Therefore, the degree of gingival inflammation can be more accurately quantified by using two parameters, ie, the color tone and the shape change of the gingiva.

The color tone analysis can be performed as follows.
First, a color digital image is formed from the surface reflected light or the internal reflected light, and then the target area to be observed in the image is divided into R, G, and B components, and the intensity of each spectral component is measured. If necessary, the measured values are averaged, and the reflected light intensity of each spectral component is calculated. By the way, in general, the spectral sensitivity of the imaging device and the color matching function of the visual system are different, so that the output (R, G, B) unique to the imaging device and the tristimulus values (X, Y, Z) obtained by the spectral colorimeter. ) Since the lightness index and the perceived chromaticity index (U ^* V ^* W ^* , L ^* a ^* b ^* , L ^* u ^* v ^* ) are different, the output value of the imaging device is a tristimulus value or a lightness index and a perceived color. It is desirable to convert the data to a degree index with high accuracy. Therefore, such conversion is also performed for the reflected light intensity of each of the above-described spectral components. As the conversion unit, the conversion may be performed using the average value of the target area, or the conversion may be performed in pixel units. However, in order to accurately reproduce the color of a fine area, it is preferable to perform conversion in pixel units. As a conversion method,
It is possible to obtain the conversion coefficient between the RGB output value when the standard color chart is imaged and the colorimetric value of the spectral colorimeter, but the standard color chart for the gingival area should be used as the standard color chart to be used. Is desirable.

On the other hand, in the observation of the gingiva, in order to improve the sharpness of the gingival surface reflected light image and to more accurately analyze and evaluate the gingival surface condition, the human reflected light component of the surface reflected light component is examined. It is effective to form a surface reflected light image by using a surface reflected light component of a spatial frequency belonging to the equivalent visual band of.

That is, Granger et al. Assume that the visual system has sensitivity only in the spatial frequency band of 10 to 40 lines / mm (3.5 to 13 CPD) on the retina, and the equivalent visual band (E
(E. M. Granger, KN Cup).
ery, “An Optical Merit Fun
ction (SQF), while correlat
es with subjective Image
Judgments ", Photogr. Sci.
Eng. , 16 , 221 (1972)).

Therefore, also in the present invention, of the gingival surface reflected light component, preferably the gingival surface reflected light component obtained according to the gingival observation method of the present invention, the spatial frequency of which falls within the range of the equivalent visual band. To form a surface reflected light image. As a result, the formed image is clearly and highly sensitively recognized by the human visual system. Furthermore, of the gingival surface reflected light components, the power of those whose spatial frequency belongs to the range of the equivalent visual band is integrated, and the integrated value is used as an index to more accurately evaluate the gingival surface condition. It becomes possible.

As an apparatus for implementing the gingival observation method of the present invention, as shown in the block diagram of FIG. 2, an irradiating light source is used as an irradiating means for allowing P-polarized light and S-polarized light to enter the gingiva G, respectively. 1 and a light source side polarizing filter 2 are used. In this case, a P-polarization filter 2p and an S-polarization filter 2s may be separately provided as the light source side polarization filter 2, and the P-polarization filter and the S-polarization One polarizing filter may be provided so as to perform both functions of the filter.

Further, the apparatus of the present invention has a light-receiving-side polarization filter 3 as a means for receiving the reflected light from the gingiva G, which can independently receive the S-polarized component and the P-polarized component of the reflected light. Use things. As the light-receiving-side polarization filter 3, the P-polarization filter 3p and the S-polarization filter 3s may be separately provided, and the P-polarization filter and the S-polarization filter can be appropriately changed in the installation angle of the polarization filter. A single polarizing filter that performs both functions may be provided.

At the subsequent stage of the light-receiving-side polarization filter 3, an imaging device 4 for receiving the S-polarized component and the P-polarized component of the reflected light obtained through the light-receiving-side polarization filter 3, and a control operation device 5 are sequentially provided. 4 (I (pp), I (p)
s), I (sp), and I (ss)) are converted into digital signals and input to the control arithmetic unit 5. The control arithmetic unit 5 calculates the surface reflected light image XS and the internal reflected light image XD based on the digitized signal from the image pickup device 4 according to the principle of the present invention to form a digital image. A color tone analysis is performed, and these results are output to the monitor 6. In this case, it is preferable that the digital image is visually observed on the monitor 6 so that the gingival target region to be observed is specified on the screen so that the color image signal of the specified region can be analyzed.

The irradiation light source 1, the polarizing filters 2, 3 on the light source side or the light receiving side, the image pickup device 4, and the monitor 6 can be those used in various surface observation devices. In addition, as long as the control arithmetic unit 5 incorporates an arithmetic operation according to the above-described principle of the present invention as a control content, a general computer or the like can be used.

As a specific mode of this apparatus, at least a part of the irradiating means and the light receiving means are integrated into one handy compact observation apparatus, and the other apparatus elements are connected as another apparatus. Alternatively, the individual device elements may be installed separately.

[0036]

Embodiment 1 (Configuration Example of Gingival Observation Apparatus) FIG. 3 is a schematic diagram of a gingival observation apparatus of the present embodiment.

[0037] As can be irradiated with a predetermined polarization in this apparatus the upper gingival portion G ₁ of the subject has a polarization plate 2A source 1 and its front face. The light source 1 is a 150 W xenon light source (Super Bright 152 manufactured by Kenko Corporation).
S) A polarizing plate 2A using two lamps arranged at an interval of 20 cm
Used was HN32 manufactured by Polaroid. Light source 1
The distance between the upper gingival portion G ₁ was 20 cm. Subjects were fixed so as not to move the upper jaw gingival site G ₁ at jaw brace of chair, the light source 1 is installed so that the horizontal maxillary gingiva site G _1.

Further, as the light receiving system of the reflected light from the upper jaw gingival site G _1, the still image was placed a polarizing plate 3B on the front HDTV color camera (Nikon Corporation, HQ-130
C) (Imaging device) 4 was used. The distance between the camera 4 and the upper gingival portion G ₁ was 30 cm.

As the control arithmetic unit 5, a general-purpose personal computer was used, image information was stored as a digital image, and analysis processing was performed.

In the color tone analysis of the surface reflected light image or the internal reflected light image, in order to correct the camera luminance and the external environmental conditions, the gingival color distribution of the standard color chart based on JIS Z 8721 close to the gingival color is used. Area (1.5
R, 5R, 10RP). Using these standard color charts, the RGB values of the digital image were converted into tristimulus values XYZ from the values of the gingival observation device of this example and a color difference meter (OFC-1000DP, manufactured by Nippon Denshoku Industries Co., Ltd.). In this case, the surface reflection light LSpp maxillary gingiva site G ₁ because made of the same spectral components as the light source 1 becomes achromatic, R component constituting the digital image, G and B components have the same intensity. Therefore, in analyzing the color tone of the surface reflected light, only the G component was used. In the color tone analysis of the internally reflected light, the R, G, and B components of the S-polarized light component LDps of the internally reflected light when P-polarized light was incident were used.

Example 2 (Example of Periodontal Observation) A 28-year-old male was used as a subject. The subject's chief complaint was tooth sway, with redness almost all over the gingiva and edema of the nipple. X-ray showed resorption of alveolar bone, and was determined to be periodontitis. Scaling and root planing were performed by a dentist, and brushing instruction was given at the same time. There are no notable items in this subject's general medical history.

During the treatment period of the subject, GI (gingival i
ndex), PD (pocket depth), BOP (bleeding on)
probing) was measured, and at the same time, gingival color tone analysis was performed using the above-mentioned gingival observation device of this example. In this case, for the internally reflected light, the Y value after converting the RGB values of the digital image into tristimulus values XYZ was recorded, and for the surface reflected light, the Y value calculated based on the G component of the digital image was recorded.

Table 1 shows the results.

[0044]

[Table 1] At the time of diagnosis 1 month of treatment start 3 months of treatment start 6 months of treatment start Internal reflected light Y value 26.6 21.2 16.2 13.4 Surface reflected light Y value 8.3 9.6 11.4 11.3 GI 3 210 PD (mm) 7-8 4 22 BOP 210

As can be seen from Table 1, the Y value of the internally reflected light and the Y value of the surface reflected light by the gingival observation device of this embodiment are the same as the evaluation values in the conventional evaluation methods (GI, PD, BOP). Behaved. In particular, the Y value based on the color tone analysis of the internal reflected light decreased with the improvement of the redness of the inflamed site, and the Y value based on the color tone analysis of the surface reflected light increased with the elimination of the swelling. In addition, the Y value of the surface reflected light showed a substantially constant value after 3 months of treatment when the swelling was eliminated.

From these results, it is understood that according to the present invention, the gingival state can be expressed as an objective numerical value, and the gingival image can be displayed with a texture.

Example 3 A 25-year-old man was used as a subject. In this dental examination, a light reddening was observed in the gingival papilla of the upper jaw at 1⊥1 part, and the subject was judged to have mild gingivitis with GI = 1. There are no notable items in the medical history.

The subject was given a brushing instruction by a dentist as a treatment for gingivitis.

As a subjective evaluation during treatment, three dentists each evaluated GI, and at the same time, analyzed the gingival color tone using the gingival observation device of Example 1. In this color tone analysis, the RGB values of the digital image for the internally reflected light are converted into tristimulus values X.
The Y value after conversion to YZ was recorded.

Table 2 shows the results.

[0051]

[Table 2] At diagnosis 2 weeks of treatment start 1 month of treatment 2 months of treatment start Internal reflection Y value 15.3 13.8 11.6 11.2 GI (Dentist A) 1 110 GI (Dentist B) 100 0 0 GI (Dentist C) 1 0 0 0

In this example, since the gingivitis of the subject was extremely mild, the GI judgment by the dentist during the course of treatment was delicate, and there was an individual difference between the dentists in judging whether the treatment was complete or not. On the other hand, since the Y value obtained by the gingival observation device of the present embodiment is stable at 1 month and 2 months from the start of the treatment, it is understood that the Y value is almost completely recovered at 1 month after the start of the treatment. This indicates that according to the present invention, minute differences in inflammation can be distinguished sharply.

[0053]

According to the present invention, the state of the gingiva is grasped from each of the surface reflected light and the internal reflected light, so that the information relating to the texture such as the color tone inside the gingival tissue and the surface unevenness is separated, and Information can be obtained quantitatively. Therefore, even if it is not a specialist such as a dentist or a dental hygienist, it is possible to quantitatively grasp the gingival inflammation state with a sharp sensitivity. Therefore, the patient can maintain a high level of motivation for self-care such as brushing during periodontitis treatment. In addition, since the difference between the states can be identified sharply, it is possible to obtain useful gingival information even for a specialist.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the principle of a gingival observation method of the present invention.

FIG. 2 is a block diagram illustrating a gingival observation device according to the present invention.

FIG. 3 is a schematic diagram of a gingival observation device according to the embodiment.

[Explanation of symbols]

Reference Signs List 1 light source 2 light source side polarization filter 2p light source side P polarization filter 2s light source side S polarization polarization filter 3 light reception side polarization filter 3p light reception side P polarization polarization filter 3s light reception side S polarization polarization filter 4 imaging device 5 control operation Apparatus 6 Monitor G Gingiva I (pp) Intensity of P-polarized light component of reflected light when P-polarized light is incident on gingiva I (ps) Intensity of S-polarized light component of reflected light when P-polarized light is incident on gingiva I (sp) Intensity of P-polarized light component of reflected light when S-polarized light enters gingiva I (ss) Intensity of S-polarized light component of reflected light when S-polarized light enters gingiva

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Maeda 2-1-3 Bunka, Sumida-ku, Tokyo F-term in the Kao Corporation Research Laboratory 4C061 AA08 BB02 CC06 DD00 FF40 LL08 NN01 NN05 QQ09 RR13 WW20 XX02

Claims (6)

[Claims] At least one of S-polarized light and P-polarized light is incident on the gingival surface, and the S-polarized component or P-polarized component of reflected light when S-polarized light is incident, or reflected light when P-polarized light is incident. Independently receives the S-polarized light component or the P-polarized light component, and independently obtains the surface reflected light component or the internal reflected light component when natural light is incident on the gingiva based on the received light intensity. A gingival observation method characterized by obtaining an image or an internal reflected light image. 2. The gingival observation method according to claim 1, wherein a color tone analysis is performed on the surface reflected light image or the internal reflected light image. 3. A gingival observation method, wherein a surface reflected light image is formed based on a spatial frequency component belonging to an equivalent visual band of a human visual system among gingival surface reflected light components. 4. A method of integrating the power of spatial frequency components belonging to the equivalent visual band of the human visual system among the gingival surface reflected light components, and evaluating the gingival surface condition based on this value. Gingival evaluation method. 5. Irradiation means comprising an irradiation light source and a polarizing filter, capable of independently causing S-polarized light or P-polarized light to enter the gingival surface, and reflected light by S-polarized light or P-polarized light incident on the gingiva from the irradiation means. A polarizing filter that transmits the S-polarized component or the P-polarized component, an imaging device that receives the S-polarized component or the P-polarized component transmitted through the polarizing filter, and a surface reflected light image or an internally reflected light image based on a signal from the imaging device. A gingival observation device comprising a control operation device for outputting to a monitor, and a monitor. 6. The gingival observation device according to claim 5, further comprising a color tone analysis calculating means for performing a color tone analysis on the surface reflected light image or the internal reflected light image.