Method for converting measurement value of saliva, information processing device, and program

Abstract

Provided is a method for converting measurement values related to saliva, the method including using a pre-obtained correlation relationship between an index measurement value of a prescribed measurement item that is measured in advance by using stimulation saliva and an index measurement value of a prescribed measurement item that is measured in advance using resting saliva, as a basis to acquire a conversion value when using the other of stimulation saliva or resting saliva collected from a subject, from a measurement value of a prescribed measurement item using one of stimulation saliva or resting saliva collected from the subject, at least one of the prescribed measurement items being selected from cavity-causing bacteria and ammonia.

Description

Method for converting saliva measurement value, information processing device, and program

[0001] The present invention relates to a method for converting a measurement value of saliva, an information processing device, and a program.

[0002] Knowing the risk or level of oral disease is important for preventing or treating oral disease. Oral disease risk refers to, for example, caries risk, i.e., the degree to which the oral cavity is susceptible to caries, and periodontal disease risk, i.e., the degree to which the oral cavity is susceptible to periodontal disease. Oral disease level refers to, for example, the caries risk and the level of periodontal disease. Testing the risk or level of oral disease is performed by using saliva collected from a subject as a test sample and measuring individual components or properties in the test sample that reflect the risk or level of oral disease.

[0003] A commonly used method for collecting saliva is to collect saliva that has been stored in the oral cavity for a certain period of time and then spat out (referred to as resting saliva or unstimulated saliva). Another commonly used method for collecting large amounts of saliva quickly and easily is to collect saliva secreted and spat out by chewing gum or the like (referred to as stimulated saliva). Recently, however, a method has emerged in which saliva is collected more simply by placing a mouthwash in the mouth, rinsing the mouth, and then spat out (referred to as mouthwash), which can be used for subjects who cannot chew gum or who have difficulty secreting saliva. Devices for measuring individual components or properties using mouthwash are also known.

[0004] International Publication No. 2017 / 175673 International Publication No. 2012 / 090995

[0005] When conducting tests to determine oral disease risk or oral disease level, one of the above-mentioned saliva collection methods has been used. However, different saliva collection methods may result in different amounts of components (measurement items) or ratios between components in the test sample, even when saliva is collected from the same subject. Therefore, even for the same measurement items, measurement results (measurement values) may differ. For this reason, when saliva tests are performed multiple times on the same subject, it is recommended to use a fixed saliva collection method so that results can be compared with previous results. However, depending on the saliva collection environment, it can be difficult to collect saliva using the same collection method each time. For example, there may be cases where chewing gum to obtain stimulated saliva or mouthwash to obtain a mouthwash is not available, or where there is not enough time to allow saliva to accumulate in the oral cavity for a certain period of time.

[0006] The present disclosure aims to provide a conversion method, information processing device, and program that can convert a measurement value using either stimulated saliva or resting saliva for a specified measurement item into an equivalent value using the other of stimulated saliva or resting saliva.

[0007] As a result of their diligent efforts, the inventors of the present application have discovered that for certain measurement items, there is a high correlation between measurements using stimulated saliva and measurements using resting saliva, leading to the following invention.

[0008] [1] A method for converting saliva-related measurements, the method comprising: obtaining a converted value for a measurement item using either stimulated saliva or resting saliva collected from a subject, based on a previously obtained correlation between an index measurement value for the measurement item measured using stimulated saliva and an index measurement value for the measurement item previously measured using resting saliva, from the measurement value for the measurement item using either stimulated saliva or resting saliva collected from the subject, when the other of the stimulated saliva or resting saliva collected from the subject is used, the measurement item being selected from at least one of caries-causing bacteria and ammonia. [2] The conversion method described in [1], in which the measurement item is ammonia. [3] The conversion method described in [1], in which the measurement value has a reaction system corresponding to the measurement item and is data indicating optical information of a test pad onto which either the stimulated saliva or the resting saliva has been applied. [4] An information processing device including a controller that executes, based on a previously obtained correlation between an index measurement value of a measurement item measured using stimulated saliva and an index measurement value of the measurement item previously measured using resting saliva, obtaining a converted value when either stimulated saliva or resting saliva collected from the subject is used, and outputting the converted value, wherein the measurement item is at least one selected from cariogenic bacteria and ammonia. [5] The information processing device described in [4], wherein the measurement value has a reaction system corresponding to the measurement item and is data indicating optical information of a test pad onto which either the stimulated saliva or the resting saliva has been applied. [6] The information processing device described in [4] or [5], wherein the controller obtains the converted value by executing a calculation procedure that calculates the converted value from the measurement value based on the correlation. [7] The information processing device according to [4] or [5], further comprising a storage unit that stores information indicating the correlation, and the controller acquires the information indicating the correlation by reading out the information indicating the correlation from the storage unit. [8] The information processing device according to [4] or [5], further comprising a communication interface that receives information from an external device, and the controller acquires the information indicating the correlation by receiving the information indicating the correlation from the external device through the communication interface.[9] A program that causes a computer to obtain a conversion value when using stimulated saliva or resting saliva collected from a subject from the measurement value of the measurement item using either stimulated saliva or resting saliva collected from the subject, based on the correlation between the index measurement value of the measurement item measured in advance using stimulated saliva or the index measurement value of the measurement item measured in advance using resting saliva, and output the conversion value, wherein the measurement item is selected from at least one of dental caries bacteria and ammonia.

[0009] The above program is a computer program, and a computer-readable non-transitory storage medium on which the program is recorded may also be included in the present invention.

[0010] According to the present invention, for a measurement item, a measurement value obtained using either stimulated saliva or resting saliva can be converted to a converted value obtained using the other of stimulated saliva or resting saliva, thereby enabling the measurement value of saliva collected by one collection method to be estimated from the value of saliva collected by the other collection method.

[0011] FIG. 1A shows a strip of test paper with test pads for each measurement item attached. FIG. 1B shows the components involved in the reaction system contained in the test pads for each measurement item. FIG. 2 shows an example of the configuration of a testing device. FIG. 3 is a graph and table showing the correlation between samples when the measurement item is buffer capacity. FIG. 4 is a graph and table showing the correlation between samples when the measurement item is acidity. FIG. 5 is a graph and table showing the correlation between samples when the measurement item is cariogenic bacteria. FIG. 6 is a graph and table showing the correlation between samples when the measurement item is occult blood. FIG. 7 is a graph and table showing the correlation between samples when the measurement item is protein. FIG. 8 is a graph and table showing the correlation between samples when the measurement item is white blood cells. FIG. 9 is a graph and table showing the correlation between samples when the measurement item is ammonia. FIG. 10 is a flowchart showing an example of processing by an information processing device.

[0012] <Saliva Collection Method> Saliva collected from the oral cavity as a test sample (also referred to as a specimen) includes resting saliva, stimulated saliva, and mouthwash. Resting saliva is collected by spitting out saliva that has accumulated in the oral cavity for a certain period of time (e.g., 5 minutes). Stimulated saliva is collected, for example, by chewing saliva-collecting gum for 5 minutes and then spitting out saliva that has accumulated in the oral cavity. Mouthwash is collected, for example, by holding purified water in the mouth and spitting it out. For example, mouthwash is collected by holding 3 mL of purified water (mouthwash) in the mouth, rinsing the mouth for 10 seconds, and then spitting out the resulting mouthwash. The volume of purified water and the time it is held in the mouth can be changed as needed. The obtained test sample can be used in subsequent procedures without any special pretreatment, but additional procedures such as dilution may be performed as needed. In this application, stimulated saliva and resting saliva are used as test samples.

[0013] <Measurement items> Measurement items related to saliva include buffer capacity, acidity, caries bacteria, occult blood, protein, white blood cells, and ammonia. An example of details of the indicator prescription (measurement principle) for measuring the measured values ​​of these measurement items is as follows. In this application, of the seven measurement items listed above, at least one selected from caries bacteria and ammonia is adopted as the predetermined measurement item (to be measured).

[0014] <Buffer Capacity> The buffer capacity of saliva is preferably measured using, for example, a pH indicator. The measurement principle involves contacting a test sample with an absorbent carrier pre-loaded with an acidic buffer and a pH indicator. The higher the acid buffer capacity of the indicator, the closer the indicated pH is to the saliva's natural pH, while the lower the acid buffer capacity, the closer the indicated pH is to the acidic range of the saliva's natural pH. The pH indicator may also be a mixture of multiple reagents. For example, a composite reagent of bromocresol green and bromoxylenol blue can be used. Examples of the acidic buffer include non-volatile organic acids. Examples of non-volatile organic acids include citric acid, malic acid, tartaric acid, malonic acid, oxalic acid, sulfosalicylic acid, sulfanilic acid, benzoic acid, and tricarballylic acid. Of these, tartaric acid is more preferred. Inorganic acids such as metaphosphoric acid can also be used as the acidic buffer. The acidic buffer may also be a buffer such as a mixture of potassium hydrogen phthalate and potassium phosphate. The concentration of the reagent can be set appropriately, and the reaction time can be set appropriately. In addition, the detection conditions for detecting the buffer capacity using a detection device such as the measurement device 20 described below can be set appropriately.

[0015] <Acidity> The measured value of the acidity of saliva is preferably measured using, for example, a pH indicator. Any known pH indicator can be used as the pH indicator, and it is preferable to use a pH indicator having a color change range in the pH range of 2 to 9, and it is more preferable to use a pH indicator having a color change range in the pH range of 3 to 8. For example, bromothymol blue sodium or a composite reagent of bromocresol green and bromoxylenol blue can be suitably used. The concentration of the pH indicator can be set as appropriate, and the reaction time can be set as appropriate. Furthermore, the detection conditions when detecting using a detection device such as the measuring device 20 described below can be set as appropriate.

[0016] <Caries-causing bacteria> The measurement value of caries-causing bacteria (Streptococcus mutans) is, for example, the number of caries-causing bacteria. Caries-causing bacteria can be measured, for example, by methods utilizing the reduction reaction of resazurin or methods using antibodies against Streptococcus mutans. The method utilizing the reduction reaction of resazurin is called the resazurin method. Resazurin is a redox indicator that normally exists as the oxidized blue pigment resazurin (maximum absorption wavelength 605 nm). However, it is reduced by NADH produced by the metabolism of gram-positive bacteria, including Streptococcus mutans, and converted to resorufin, a reddish-purple pigment (maximum absorption wavelength 573 nm). In other words, the reduction of resazurin progresses in response to the number of viable Streptococcus mutans bacteria. Furthermore, when using the resazurin method, the measurement reagent preferably contains 1-methoxy-5-methylphenazinium methyl sulfate (methoxy PMS) in addition to resazurin. Containing methoxy PMS is more effective for measurement under short reaction conditions at room temperature than when not containing methoxy PMS. The concentration of the reagent can be set appropriately, the reaction time can be set appropriately, and the detection conditions for detection by a detection device such as the measurement device 20 described below can be set appropriately.

[0017] <Occult Blood> Occult blood is blood in a test sample obtained from the oral cavity. The measured value of occult blood is, for example, the amount or concentration of blood in a test sample obtained from the oral cavity. It is known that occult blood is detected in saliva when gum tissue is destroyed due to periodontal disease, and occult blood is an indicator that reflects the degree of periodontal tissue destruction. The greater the amount of occult blood (occult blood volume), the greater the degree of periodontal tissue destruction and the more severe the periodontal disease stage. The method for measuring the occult blood measurement is not particularly limited and can be performed by any known method. For example, it is preferably performed by the hemoglobin contact activation method. The hemoglobin contact activation method utilizes the ability (peroxidase-like activity) of blood components such as hemoglobin, myoglobin, or their degradation products to catalyze the transfer of oxygen from oxygen donors such as peroxides to oxygen acceptors. By using an indicator that changes color upon oxidation as the oxygen acceptor, occult blood is measured through the measurement of the concentration of hemoglobin, etc. by measuring the color reaction. The concentration of the reagent can be set appropriately, the reaction time can be set appropriately, and the detection conditions for detection by a detection device such as the measurement device 20 described below can be set appropriately.

[0018] <Protein> Protein refers to a protein in a test sample obtained from the oral cavity. The measured value of protein is, for example, the concentration of total protein in a test sample obtained from the oral cavity. The higher the number of periodontal disease bacteria in the oral cavity, the higher the total protein concentration, so the total protein concentration is an item that reflects the number of periodontal disease bacteria. The higher the total protein concentration, the more severe the stage of periodontal disease tends to be. The method for measuring the measured protein value is not particularly limited and can be performed using a known method. For example, the protein error method is preferable. The protein error method utilizes the fact that a pH indicator indicates a pH higher than the true pH of the solution in proportion to the protein concentration, and protein can be quantified from the color change of the indicator. The concentration of the reagent can be set appropriately, and the reaction time can be set appropriately. Furthermore, the detection conditions for detection using a detection device such as the measuring device 20 described below can be set appropriately.

[0019] <Leukocytes> Leukocytes are white blood cells in a test sample obtained from the oral cavity. The measured value of white blood cells is, for example, the number of white blood cells (leukocyte count) in a test sample obtained from the oral cavity. It is known that white blood cells gather at sites affected by periodontal disease (sites of inflammation), and the white blood cell count is an item that reflects the degree of inflammation in periodontal tissue. The higher the white blood cell count, the higher the degree of inflammation in periodontal tissue and the more severe the stage of periodontal disease tends to be. The method for measuring the measured value of white blood cells is not particularly limited and can be performed by any known method. For example, it is preferably performed by the leukocyte esterase method. The leukocyte esterase method utilizes the fact that when tissue inflammation occurs, the number of white blood cells increases, and the production of esterase by white blood cells also increases accordingly. This method uses an ester compound as a substrate, which is hydrolyzed by esterase (leukocyte esterase) produced by leukocytes to produce an alcohol (phenol) component, which is then directly colored, or the alcohol (phenol) is coupled with a diazonium salt to produce a color, thereby measuring esterase activity. The leukocyte count can be calculated based on the measured value of esterase activity. The concentration of the reagent and the reaction time can be set appropriately. Furthermore, the detection conditions for detection using a detection device such as the measuring device 20 described below can be set appropriately.

[0020] <Ammonia> Ammonia is the ammonia in a test sample obtained from the oral cavity. The measured value of ammonia is, for example, the concentration of ammonia (ammonia concentration) in a test sample obtained from the oral cavity. The more actively bacteria, including periodontal disease bacteria, grow in the oral cavity, the higher the ammonia concentration, so ammonia is an item that reflects the number of oral bacteria. The higher the ammonia concentration, the more severe the stage of periodontal disease tends to be. The method for measuring the measured value of ammonia is not particularly limited and can be performed by a known method. For example, the microdiffusion method (Conway method) is preferred. The microdiffusion method is a technique used to quantify ammonia nitrogen. Ammonia gas volatilized from a test sample made alkaline with an alkaline buffer is trapped in an absorption solution or the like, and the color change of an indicator is quantified by a method such as colorimetry. Another applicable method is the ammonia quantification method disclosed in Japanese Patent No. 7,328,739. The ammonia quantification method involves performing a glutamate synthetase reaction using an ammonia-containing sample, such as saliva, and quantifying ammonia in the ammonia-containing sample based on the amount of ammonia consumed in the reaction. A chelating agent is present in the glutamine synthetase reaction system. Any chelating agent can be used as long as it can chelate calcium ions. Ammonia is consumed by the glutamine synthetase reaction, producing equimolar amounts of ADP and phosphate (orthophosphate) as ammonia. Ammonia can be quantified by measuring the amount of ADP or phosphate produced or the amount of reaction product using ADP or phosphate. The ammonia quantification reagent used in the quantification method may contain the chelating agent described above, glutamine synthetase, ATP, and glutamic acid. When quantifying the amount of ammonia based on the ADP or phosphate produced by the glutamine synthetase reaction, the ammonia quantification reagent preferably contains a reagent for measuring the amount of ADP or phosphate. The concentrations of the reagents can be set as appropriate, and the reaction time can be set as appropriate. Furthermore, the detection conditions for detection by a detection device such as the measuring device 20 described below can be set appropriately.

[0021] <Correlation> In the present application, it has been found that, for the above-mentioned measurement items, measurement values ​​measured using either stimulated saliva or resting saliva collected from a subject have a high correlation with measurement values ​​measured using the other of stimulated saliva or resting saliva collected from the same subject. Based on this correlation, the present invention obtains a converted value when the other of stimulated saliva or resting saliva collected from a subject is used from the measurement value of a predetermined measurement item measured using either stimulated saliva or resting saliva collected from a subject (i.e., converts the measurement value into a converted value).

[0022] Here, correlation refers to a relationship between two things or values, and indicates that when one increases or decreases, the other also tends to increase or decrease. Correlation can be shown, for example, using a simple regression equation (y = ax + b) based on a simple regression analysis using measured values ​​when stimulated saliva and measured values ​​when resting saliva is used. In the simple regression equation, x is the explanatory variable, y is the dependent variable, a is the regression coefficient, and b is the intercept. The explanatory variable x represents the measured value of either stimulated saliva or resting saliva, and the dependent variable y represents the measured value of the other, stimulated saliva or resting saliva.

[0023] In this specification, the measured values ​​of stimulated saliva or resting saliva obtained to derive (create) the correlation indicated by the above-mentioned simple regression equation are referred to as index measured values. In other words, the measured values ​​of stimulated saliva or resting saliva measured to obtain the regression line in the above-mentioned simple regression equation correspond to index measured values. For example, the above-mentioned simple regression equation is used as a conversion equation. The measured value of either stimulated saliva or resting saliva collected from the subject is substituted into the simple regression equation as the explanatory variable x. The substitution calculates the dependent variable y, and the calculated dependent variable y is treated as the converted value of the other, stimulated saliva or resting saliva.

[0024] The number of measurements of the index measurement value to obtain the correlation can be any number. The number of measurements of stimulated saliva to obtain the index measurement value and the number of measurements of resting saliva can be the same or different. Furthermore, as long as an increase or decrease in one is shown to be associated with an increase or decrease in the other, the correlation can be expressed using something other than a simple regression equation.

[0025] The index measurement value for a measurement item may be a value indicating primary data used to calculate the measurement value of a specified measurement item. The primary data may, for example, have a reaction system corresponding to the specified measurement item and may be data indicating optical information such as the reflectance or transmittance of a test pad onto which stimulated saliva or resting saliva has been applied. The index measurement value may also be a value indicating the quantity of a specified measurement item calculated from the primary data using a calibration curve or an arithmetic formula. In other words, the index measurement value may be information that directly indicates a quantity indicating the measurement item, or information that indirectly indicates a quantity indicating the measurement item, such as reflectance. The sample provider from whom the index measurement value is obtained and the subject from whom the measurement value is obtained may be the same person or different people.

[0026] Like index measurements, the measured values ​​of the measurement items related to stimulated saliva or resting saliva collected from a subject may be values ​​representing primary data used to calculate the measurement values ​​of the specified measurement items. The primary data may, for example, have a reaction system corresponding to the specified measurement item and may be data representing optical information such as the reflectance or transmittance of a test pad onto which stimulated saliva or resting saliva has been applied. Furthermore, the measured values ​​may be values ​​representing the quantity of the specified measurement item calculated from the primary data using a calibration curve or an arithmetic formula. In other words, the measured values ​​may be information directly indicating the quantity representing the measurement item, or information indirectly indicating the quantity representing the measurement item, such as reflectance.

[0027] Hereinafter, a method for converting a measurement value related to saliva and an information processing device used therein according to this embodiment will be described with reference to the drawings. The examples described below are merely examples, and the present invention is not limited to these examples.

[0028] FIG. 1A shows an example of a strip-shaped test paper 31 with test pads 31a-31g attached, each impregnated with indicators (components involved in the reaction system) for measuring the seven measurement items described above. Test pad 31a is used to measure buffer capacity. Test pad 31b is used to measure acidity. Test pad 31c is used to measure caries bacteria. Test pad 31d is used to measure occult blood. Test pad 31e is used to measure protein. Test pad 31f is used to measure white blood cells. Test pad 31f is used to measure ammonia. FIG. 1B shows the components involved in the reaction system contained in test pads 31a-31g for each measurement item. When a test sample is applied to test pads 31a-31g of strip-shaped test paper 31, the color changes due to the reaction principle associated with each measurement item described above. The color is measured using a measuring device 20 (FIG. 2).

[0029] 2 shows an example configuration of an inspection device 30. The inspection device 30 includes an information processing device 10 and a measurement device 20. The information processing device 10 is a dedicated or general-purpose computer such as a personal computer (PC), a workstation, or a smart device (smartphone, tablet terminal). The information processing device 10 includes a processor 11 (corresponding to a control unit or controller), a storage device 15 (corresponding to a storage unit), an input device 12, a display (display device) 14, and a communication interface (communication IF) 16, all of which are connected to a bus B. The measurement device 20 and an output device 40 are electrically connected to the bus B of the information processing device 10 via an interface circuit (I / F).

[0030] The measuring device 20 measures the buffer capacity, acidity, caries-causing bacteria, occult blood, protein, white blood cells, and ammonia as predetermined measurement items in a test sample obtained from the subject's oral cavity. The measuring device 20 measures the color tone of the test pads 31a-31g onto which the test sample is applied using reflectometry and calculates (detects) the reflectance. The measurement values ​​of each measurement item are obtained from the reflectance. The measuring device 20 can be, for example, the "SillHa" measuring device, which can measure six of the seven measurement items listed above, excluding occult blood, or the "ST-4910" measuring device, which can measure all seven of the seven measurement items listed above (both manufactured by Arkray). Furthermore, strip-shaped test papers 31 capable of measuring each measurement item corresponding to these measuring devices can be used. The measuring device 20 can be configured with one or more measuring devices capable of measuring one or more measurement items. Furthermore, the number of strip-shaped test papers and the number of test pads on each strip-shaped test paper are arbitrary as long as measurement results for the predetermined measurement items can be obtained. However, reflectance photometry is just one example of a method for measuring each measurement item, and other measurement methods may be used, and the measuring device 20 is not limited to the above-described configuration. Furthermore, the measurement method may be appropriately set depending on the prescription of the indicator (measurement principle) for the measurement item.

[0031] The storage device 15 includes a main storage device and an auxiliary storage device. The storage device 15 stores programs executed by the processor 11 and data used when executing the programs. The storage device 15 includes a read-only memory (ROM), a random access memory (RAM), a hard disk, a solid-state drive (SSD), etc. The storage device 15 may be installed (fixed) in the information processing device 10 or may be detachable (e.g., a USB memory) connected to the information processing device 10 via a universal serial bus (USB) connector or the like. As described below, the storage device 15 stores information indicating a correlation. For example, if the information indicating the correlation is a simple regression equation, the storage device 15 can also store information indicating this simple regression equation as data. The information indicating the correlation can be stored in the form of a program that calculates a response variable y (converted value) by substituting an explanatory variable x (measured value), or in the form of reading the corresponding response variable y from a correspondence table in response to the input of the explanatory variable x. Alternatively, the information indicating the correlation can be stored in the form of a program that queries a communication partner (such as a server connected to the information processing device 10 via a network) for a target variable y corresponding to an input explanatory variable x, and receives the corresponding target variable y as a response to the query.

[0032] The input device 12 is a key, button, touch panel, or the like, and is used to input data. Measurement values ​​of the measuring device 20 may be input (received) to the information processing device 10 as data signals indicating the measurement results from the measuring device 20 via an interface, or may be manually input using the input device 12. The display 14 displays data and information. The communication IF 16 can also be used to communicate with external devices and obtain information indicating correlations through communication with external devices. Data indicating measurement values ​​may be obtained via wireless communication with the measuring device 20. The communication IF 16 may be installed (fixedly arranged) in the information processing device 10, or may be detachable via a USB connector or the like.

[0033] The processor 11, which serves as a controller, is a CPU (Central Processing Unit) or the like, and performs various processes by executing programs stored in the storage device 15. For example, by executing the programs, the processor 11 can convert measured values ​​into equivalent values ​​based on the above-described correlation. That is, based on the correlation, the processor 11 can convert measured values ​​using resting saliva into equivalent values ​​using stimulated saliva. Furthermore, based on the correlation, the processor 11 can convert measured values ​​of measurement items using stimulated saliva into equivalent values ​​using resting saliva.

[0034] As described above, the conversion from a measured value to a converted value can be performed, for example, by substituting the measured value, which is the explanatory variable x, into a simple regression equation (y = ax + b) indicating the correlation and calculating the response variable y as the converted value. The storage device 15 can store a program including an algorithm (calculation procedure) for calculating the converted value from the measured value using the conversion equation. For example, when a measured value, which is the explanatory variable x, is acquired by inputting it to the information processing device 10 or receiving it by the information processing device 10, the processor 11 can calculate the converted value, which is the response variable y, by executing a calculation procedure for calculating the response variable y using the explanatory variable x and the regression coefficient a and intercept b previously stored in the storage device 15. Alternatively, the conversion from a measured value to a converted value can be performed by, for example, using the above-mentioned correlation (simple regression equation) to previously store the correspondence between the measured value (explanatory variable x) and the converted value (response variable y) in the storage device 15, and when a measured value is acquired, the processor 11 reads out the converted value corresponding to the measured value from the storage device 15. The correspondence can be stored using various data structures, such as a correspondence table between measurement values ​​and converted values ​​or a relational database. Alternatively, the conversion from a measurement value to a converted value may be performed by the processor 11 requesting or inquiring about a converted value from another device (communication partner) when a measurement value is acquired, and then receiving (acquiring) the converted value transmitted in response to the request or inquiry. The converted value may be displayed on the display 14, output from an output device such as a printer, or transmitted as data or a signal indicating the converted value. Alternatively, the information processing device 10 may acquire information indicating the correlation through communication using the communication IF 16, and perform the conversion described above using the acquired information indicating the correlation.

[0035] The processor 11 can also determine, for example, the stage of periodontal disease from the measured values ​​or converted values ​​of the measurement items and generate information indicating the periodontal disease stage determination result. The generated information may be displayed on the display 14. Alternatively, the information may be printed by an output device 40 such as a printer. The information may also be transmitted to a communication partner using the communication IF 16. The processor 11 may be a device other than a CPU (such as a DSP (Digital Signal Processor) or a GPU (Graphical Processing Unit)). The processing performed by the processor 11 may also be performed by a combination of multiple types of processors, a field programmable gate array (FPGA), a complex programmable logic device (CPLD), or an integrated circuit such as an application specific integrated circuit (ASIC), or a system-on-a-chip (SoC).

[0036] Example: Mouthwash, resting saliva, and stimulated saliva were collected from the same subject's mouth using the saliva collection method described above. Mouthwash was collected by holding 3 mL of purified water in the mouth and rinsing for 10 seconds, followed by spitting out the resulting mouthwash. Resting saliva was collected by spitting out saliva that had accumulated in the mouth for 5 minutes. Stimulated saliva was collected by chewing saliva-collecting gum for 5 minutes and then spitting out saliva that had accumulated in the mouth. The following experiment was conducted to confirm whether there was a correlation between the measurements of each measurement item (buffer capacity, acidity, caries-causing bacteria, occult blood, protein, leukocytes, and ammonia) in samples collected using these different collection methods. For those collection methods where a correlation was confirmed, the following experiment was conducted to determine a conversion formula for converting measurements of a given measurement item measured using one method to the equivalent value when using the other method. The mouthwash was an undiluted solution (i.e., a solution that was not diluted), and the resting saliva and stimulated saliva were prepared by diluting the undiluted solution five times with purified water (distilled water).

[0037] The number of specimens (n ​​= 15) for measuring buffer capacity was 15, the number of specimens for measuring pH and mutans streptococcus count was 20, the number of specimens for measuring occult blood volume and total protein concentration was 12, the number of specimens for measuring leukocyte count was 17, and the number of specimens for measuring ammonia concentration was 8.

[0038] Using strip test paper 31 (Figure 1) and measuring device 20 (SillHa, ST-4910 for occult blood), buffer capacity, acidity, cariogenic bacteria, occult blood, protein, leukocytes, and ammonia were measured for each sample. Strip test paper 31 has test pads 31a-31g corresponding to each measurement item. Test pads 31a-31g contain components involved in the reaction system corresponding to each measurement item (Figure 1B). The measuring device 20 measured the reflectance of test pads 31a-31g of strip test paper 31, on which saliva (the test sample) was applied. Measurements of cariogenic bacteria, leukocytes, and ammonia were performed once for each sample. Measurements of buffer capacity, acidity, occult blood, and protein were performed twice for each sample, and the average values ​​were calculated. In other words, in this embodiment, for dental caries bacteria, white blood cells, and ammonia, the measurement value obtained from a single measurement corresponds to the index measurement value, and for buffer capacity, acidity, occult blood, and protein, the average value of the measurement value obtained from two measurements corresponds to the index measurement value for each specified measurement item.

[0039] FIG. 3 shows a graph and a table illustrating the correlation between samples when the measurement item is buffer capacity. The graph on the left side of FIG. 3 plots the buffer capacity index measurement values ​​(reflectance of the test pad 31a) for each of the mouthwash and resting saliva, and further draws a regression line, showing the correlation between the index measurement values ​​for the mouthwash and the resting saliva. The vertical axis of the left graph is the reflectance [%] of the test pad 31a on which resting saliva has been applied, and the horizontal axis is the reflectance [%] of the test pad 31a on which mouthwash has been applied. The central graph plots the buffer capacity index measurement values ​​for each of the mouthwash and stimulated saliva, showing the correlation between the mouthwash and stimulated saliva. The vertical axis of the central graph is the reflectance [%] of the test pad 31a on which stimulated saliva has been applied, and the horizontal axis is the reflectance [%] of the test pad 31a on which mouthwash has been applied. The graph on the right plots the measured values ​​of the buffer capacity index for both resting saliva and stimulated saliva, showing the correlation between resting saliva and stimulated saliva. The vertical axis of the graph on the right represents the reflectance [%] of the test pad 31a to which stimulated saliva has been applied, and the horizontal axis represents the reflectance [%] of the test pad 31a to which resting saliva has been applied. Note that the vertical and horizontal axes may be reversed, i.e., the explanatory variable x and the objective variable y of the simple regression equation showing the regression line may be reversed.

[0040] Here, the correlation between samples is such that plots of the index measurement values ​​of each sample yield a correlation coefficient of 0.6 or higher, which means that the samples can be converted to each other. Furthermore, a correlation coefficient of 0.7 or higher is considered to be even more correlated, resulting in high accuracy when converted to each other. Furthermore, a correlation coefficient of 0.8 or higher is considered to be even more correlated, resulting in very high accuracy when converted to each other. The correlation coefficient is not limited to calculations based on plots of the index measurement values ​​of each sample; any known method for quantifying a correlation can be used. Depending on the measurement method and measurement principle, a correlation coefficient of less than 0.6 may be acceptable. However, in this example, a model (y = ax + b) with a correlation coefficient of 0.6 or higher was used as the conversion formula between samples. The same applies to parameters other than buffer capacity.

[0041] The table in Figure 3 shows the correlation coefficient between the mouthwash and resting saliva, the correlation coefficient between the mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.77, 0.27, and 0.37, respectively. As a result, it was determined that there was a correlation only between the mouthwash and resting saliva with regard to buffer capacity. In addition, the model between the mouthwash and resting saliva was y = 0.7118x + 0.7695 (decision function R ２ = 0.4562) can be used as a conversion formula between mouthwash (x) and resting saliva (y).

[0042] 4 shows graphs and tables showing correlations between samples when the measurement item is acidity, and are formatted in the same manner as the graphs and tables showing correlations between samples when the measurement item is buffer capacity. Each graph shows a plot of the pH index measurement value (reflectance of the test pad 31b) and a regression line, showing the correlation between the index measurements of each sample.

[0043] The table in Figure 4 shows the correlation coefficient between the mouthwash and resting saliva, the correlation coefficient between the mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.73, 0.54, and 0.41, respectively. As a result, it was determined that there was a correlation only between the mouthwash and resting saliva with regard to acidity. In addition, the model between the mouthwash and resting saliva was y = 0.6866x + 21.105 (decision function R ２ = 0.5305) can be used as a conversion formula between mouthwash (x) and resting saliva (y).

[0044] 5 shows a graph and table showing the correlation between samples when the measurement item is cariogenic bacteria, and has the same format as the graph and table showing the correlation between samples when the measurement item is buffer capacity. Each graph shows a plot of the index measurement value of cariogenic bacteria (reflectance of test pad 31c) and a regression line, and shows the correlation between the index measurement values ​​of each sample.

[0045] The table in Figure 5 shows the correlation coefficient between mouthwash and resting saliva, the correlation coefficient between mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.68, 0.66, and 0.74, respectively. As a result, it was determined that there was a correlation between all samples for caries-causing bacteria. In addition, the model between mouthwash and resting saliva was y = 0.7118x + 0.7695 (decision function R ２ = 0.4562) can be used as a conversion formula between the mouthwash (x) and the resting saliva (y). In addition, the model between the mouthwash and the stimulated saliva is y = 0.6211x + 1.2692 (decision function R ２ = 0.4364) can be used as a conversion formula between the mouthwash (x) and stimulated saliva (y). Furthermore, the model between resting saliva and stimulated saliva, y = 0.6634x + 1.4974 (decision function R ２ = 0.5528) can be used as a conversion formula between resting saliva (x) and stimulated saliva (y).

[0046] 6 shows graphs and tables showing correlations between samples when the measurement item is occult blood, and are formatted in the same manner as the graphs and tables showing correlations between samples when the measurement item is buffer capacity. Each graph shows a plot of the occult blood indicator measurement value (reflectance of the test pad 31d) and a regression line, showing the correlation between the indicator measurements of each sample.

[0047] The table in Figure 6 shows the correlation coefficient between the mouthwash and resting saliva, the correlation coefficient between the mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.74, 0.61, and 0.19, respectively. With regard to occult blood, it was determined that there was a correlation between the mouthwash and resting saliva, and between the mouthwash and resting saliva. In addition, the model between the mouthwash and resting saliva was y = 1.1852x + 6.5379 (decision function R ２ = 0.55472) can be used as a conversion formula between the mouthwash (x) and the resting saliva (y). In addition, the model between the mouthwash and the stimulated saliva is y = 0.7237x + 22.749 (decision function R ２ = 0.3669) can be used as a conversion formula between the mouthwash (x) and stimulated saliva (y).

[0048] 7 shows graphs and tables showing correlations between samples when the measurement item is protein, and are formatted in the same manner as the graphs and tables showing correlations between samples when the measurement item is buffer capacity. Each graph shows a plot of the occult blood indicator measurement value (reflectance of the test pad 31e) and a regression line, showing the correlation between the indicator measurements of each sample.

[0049] The table in Figure 7 shows the correlation coefficient between the mouthwash and resting saliva, the correlation coefficient between the mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.83, 0.27, and 0.24, respectively. With regard to protein, it was determined that there was a correlation only between the mouthwash and resting saliva. In addition, the model between the mouthwash and resting saliva was y = 1.2272x + 18.351 (decision function R ２ = 0.5872) can be used as a conversion formula between mouthwash (x) and resting saliva (y).

[0050] 8 shows graphs and tables showing correlations between samples when the measurement item is white blood cells, and has the same format as the graphs and tables showing correlations between samples when the measurement item is buffer capacity. Each graph shows a plot of the white blood cell index measurement value (reflectance of the test pad 31f) and a regression line, showing the correlation between the index measurements of each sample.

[0051] The table in Figure 8 shows the correlation coefficient between the mouthwash and resting saliva, the correlation coefficient between the mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.79, 0.93, and 0.58, respectively. With regard to white blood cells, it was determined that there was a correlation between the mouthwash and resting saliva, and between the mouthwash and stimulated saliva. In addition, the model between the mouthwash and resting saliva was y = 1.2594x + 1.0453 (decision function R ２ = 0.6317) can be used as a conversion equation between mouthwash (x) and resting saliva (y). In addition, the model between mouthwash and stimulated saliva is y = 0.8776x + 14.429 (decision function R ２ = 0.8586) can be used as a conversion formula between the mouthwash (x) and stimulated saliva (y).

[0052] 9 shows graphs and tables illustrating correlations between analytes when the measurement item is ammonia, and are formatted in the same manner as the graphs and tables illustrating correlations between analytes when the measurement item is buffer capacity. Each graph shows a plot of the ammonia index measurement value (reflectance of test pad 31g) and a regression line, showing the correlation between the index measurements of each analyte.

[0053] The table in Figure 9 shows the correlation coefficient between the mouthwash and resting saliva, the correlation coefficient between the mouthwash and stimulated saliva, and the correlation coefficient between resting saliva and stimulated saliva. The correlation coefficients were 0.83, 0.59, and 0.73, respectively. With regard to ammonia, it was determined that there was a correlation between the mouthwash and resting saliva, and between the mouthwash and resting saliva. In addition, the model between the mouthwash and resting saliva was y = 0.9156x + 5.9977 (decision function R ２ = 0.6812) can be used as a conversion formula between the mouthwash (x) and the resting saliva (y). In addition, the model between the resting saliva and the stimulated saliva is y = 0.3189x + 27.477 (decision function R ２ = 0.5326) can be used as a conversion formula between the mouthwash (x) and stimulated saliva (y).

[0054] From the above, it was found that conversion is possible for at least one of caries bacteria or ammonia when the correlation coefficient of the plot of index measurement values ​​between stimulated saliva and resting saliva is 0.6 or higher. It was also found that for ammonia when the correlation coefficient is 0.7 or higher, conversion accuracy is high. A program capable of converting the measurement value (reflectance) of at least one of caries bacteria and ammonia measured using either stimulated saliva or resting saliva into a conversion value when the other of stimulated saliva or resting saliva is used is installed in the storage device 15 of the information processing device 10.

[0055] <Measurement with Test Device> Next, a description will be given of a measurement method using the strip-shaped test paper 31 and the test device 30. Fig. 10 is a flowchart showing an example of processing in the information processing device 10. The processing in each step in Fig. 10 is performed by the processor 11, which is a controller.

[0056] (1) Information about the subject (e.g., a patient) is input to the information processing device 10 using the input device 12 and stored in the storage device 15 (S01 in FIG. 10). (2) Saliva is collected from the subject using one of the following methods: collecting mouthwash, collecting resting saliva, or collecting stimulated saliva. (3) The sample to be measured is prepared according to the method used for collecting the saliva. Specifically, as in the above-described embodiment, if the collected sample is resting saliva or stimulated saliva, the sample is diluted five times with purified water. (4) The sample is applied to the test pads 31a to 31g (FIG. 1) for each measurement item on the strip-shaped test paper 31. (5) After application, the strip-shaped test paper 31 is placed in the measurement device 20. (6) The measurement device 20 measures the specified measurement items (in this embodiment, buffer capacity, acidity, caries bacteria, occult blood, protein, white blood cells, and ammonia) and obtains the respective measurement values.

[0057] (7) A signal indicating each measurement value is sent from the measuring device 20 to the information processing device 10, and data indicating each measurement value is stored in the storage device 15 (S02 in FIG. 10). (8) Information indicating the saliva collection method (referred to as Method A) performed in (2) above is input to the information processing device 10 using the input device 12 or the like (S03 in FIG. 10).

[0058] (9) Information specifying a saliva collection method (referred to as Method B) different from Method A and information specifying the measurement items desired to be converted into measurement values ​​by Method B are input (S04 in FIG. 10). Note that the order in which Method A, Method B, and the measurement method are input is arbitrary, and they can be input at any timing in steps (1) to (8).

[0059] (10) When a conversion trigger occurs in the information processing device 10 (for example, when an instruction to perform conversion is input, or when an operation to confirm the input of method B and a measurement item is performed), the processor 11 of the information processing device 10 executes a program to convert the measurement value related to method A into a converted value related to method B (S05 in FIG. 10). As an example, the processor 11 calculates the converted value from the measurement value by performing a calculation in accordance with a calculation procedure for calculating the converted value from the measurement value of the measurement item.

[0060] (11) The converted value is output (S06 in FIG. 10). The converted value may be displayed on the display 14 or printed by the output device 40 under the control of the processor 11. If there are any measured values ​​that were not subject to conversion, those measured values ​​may be displayed or printed together with the converted value. Alternatively, the measured values ​​before conversion may be displayed together with the converted value. Alternatively, the conversion formula may be displayed or printed together with the converted value.

[0061] (12) As other processing (S07 in FIG. 10), the processor of the information processing device 10 uses the measured values ​​and converted values ​​to make a determination regarding the periodontal disease stage, caries risk, periodontal disease risk, etc., and can display the periodontal disease stage determination results on the display 14 or print them out using the output device 40. In this way, a test for determining oral disease risk or oral disease level is provided.

[0062] In the above-described embodiment, the information processing device 10 acquires the reflectance, which is the primary data of the measurement item measured by the measuring device 20, as a measurement value, and the processor 11 of the information processing device 10 converts the measurement value (reflectance) into a converted value (reflectance). However, the information processing device may acquire, instead of the reflectance, a value indicating the quantity of the measurement item calculated from the reflectance as a measurement value from the measuring device 20 or the like, and convert the measurement value into a converted value using a conversion formula based on the value indicating the quantity.

[0063] According to the information processing device of the embodiment, for at least one of the seven measurement items described above, cariogenic bacteria and ammonia, the measurement values ​​using a sample collected by Method A (either stimulated saliva or resting saliva) can be converted to equivalent values ​​when collected by Method B (the other of stimulated saliva or resting saliva). This allows, for example, when performing multiple measurements using resting saliva, even if a certain amount of time is not available to obtain resting saliva for a certain measurement, converting the measurement values ​​into equivalent values ​​can obtain values ​​equivalent to those when using resting saliva. The same applies when performing multiple measurements using stimulated saliva, even if one or more measurements using resting saliva are performed. In other words, even if measurements using stimulated saliva and measurements using resting saliva are mixed, these results can be treated as if either stimulated saliva or resting saliva were used. In other words, it is possible to estimate the measurement values ​​of saliva collected by one collection method from the measurement values ​​of saliva collected by the other collection method. This makes it possible to accurately perform various assessments (e.g., assessments related to caries risk and periodontal disease risk) using the measurement results of saliva collected by different collection methods as a test for determining the risk or level of oral disease. The configurations described in the embodiments can be combined as appropriate.

Claims

1. A method for converting measurement values ​​related to saliva, comprising obtaining a conversion value for a measurement item using either stimulated saliva or resting saliva collected from a subject, based on a previously obtained correlation between an index measurement value of the measurement item previously measured using stimulated saliva and an index measurement value of the measurement item previously measured using resting saliva, wherein the measurement item is at least one selected from among caries-causing bacteria and ammonia.

2. The method according to claim 1, wherein the measurement item is ammonia.

3. The conversion method according to claim 1, wherein the measurement value has a reaction system corresponding to the measurement item and is data showing optical information of a test pad onto which either the stimulated saliva or the resting saliva has been applied.

4. An information processing device including a controller that obtains a conversion value from the measurement value of the measurement item using either stimulated saliva or resting saliva collected from the subject, based on a previously obtained correlation between an index measurement value of the measurement item previously measured using stimulated saliva and an index measurement value of the measurement item previously measured using resting saliva, and outputs the conversion value, wherein the measurement item is selected from at least one of caries-causing bacteria and ammonia.

5. An information processing device according to claim 4, wherein the measurement value has a reaction system corresponding to the measurement item and is data showing optical information of a test pad onto which either the stimulated saliva or the resting saliva has been applied.

6. The information processing device according to claim 4 or 5, wherein the controller acquires the converted value by executing a calculation procedure for determining the converted value from the measured value based on the correlation.

7. An information processing device according to claim 4 or 5, further comprising a memory unit that stores information indicating the correlation, and wherein the controller obtains the information indicating the correlation by reading the information indicating the correlation from the memory unit.

8. An information processing device as described in claim 4 or 5, further comprising a communication interface for receiving information from an external device, wherein the controller acquires the information indicating the correlation by receiving the information indicating the correlation from the external device via the communication interface.

9. A program that causes a computer to obtain a conversion value from the measurement value of a measurement item using either stimulated saliva or resting saliva collected from a subject, based on the correlation between an index measurement value of the measurement item measured in advance using stimulated saliva and an index measurement value of the measurement item measured in advance using resting saliva, and to output the conversion value, wherein the measurement item is at least one selected from among caries-causing bacteria and ammonia.

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