JP2001061873A - Persistent tooth anticipation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a persistent tooth anticipation system for determining the rate of decrease in a total effective root surface area from a current total effective root surface area and anticipating the rate of decrease in number of persistent teeth from the result. SOLUTION: This persistent tooth anticipation system calculates a decrease curve or decrease straight line of a total effective root surface area due to aging, from a patient's current age, current total effective root surface area, and number of teeth lost by disease. The persistent tooth anticipation system allows anticipation of such an easy-to-understand item as number of persistent teeth by outputting the decrease curve or decrease straight line of the total effective root surface area, and the number can be used as material for long- term tooth protection, treatment and instructions. The decrease curve or decrease straight line of the total effective root surface area can be determined using values that can be non-destructively and easily measured, whereby the persistent tooth anticipation system can be utilized readily and the number can be easily provided as the material for long-term tooth protection, treatment and instructions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remaining tooth prediction system for predicting the degree of reduction of remaining teeth. More specifically, the present invention relates to a remaining tooth prediction system that determines the degree of decrease in the total effective root surface area based on the currently measured current effective root area, and predicts the degree of decrease in the number of remaining teeth based on the result. The results obtained by this residual tooth prediction system are used as data for long-term prevention, treatment and guidance of teeth.

[0002]

2. Description of the Related Art After a human tooth has changed from a milk tooth to a permanent tooth, it does not change throughout the life. However, many people lose permanent teeth as they age due to dental caries (also called tooth decay) and periodontal disease. At the age of 80, the number is often less than 20. For this reason, it is difficult to sufficiently chew with own teeth. However, since it is preferable that the remaining teeth have no disease and that it is possible to chew normally with their own teeth, treatment and prevention are often performed so that even elderly people can maintain a large number of chewable own teeth. .

It can be said that it is preferable to set a target for such treatment and prevention. An example of such a goal is the 8020 exercise advocated by the Ministry of Health and the Japanese Dental Association. In this 8020 exercise, at the age of 80, 2
It works to maintain zero or more teeth.

[0004]

In order to achieve the above-mentioned goals, it is difficult to achieve prevention and treatment only by performing prevention and treatment according to the current situation, and it is difficult to achieve long-term diseases and the number of teeth. It is desirable to grasp the progress and provide guidance including prevention and treatment according to the progress. Also, prevention and treatment from a young age is important. However, no means has been provided for predicting the future based on past progress. In addition, since patients do not always go to a specific dentist for a long period of time, it is difficult to keep track of the past.

[0005] The present invention has been made to solve such problems, and is an index of long-term prevention and treatment of teeth.
An object of the present invention is to provide a remaining tooth prediction system for predicting the degree of decrease in remaining teeth.

[0006]

The remaining tooth prediction system according to the first aspect of the present invention uses at least the present age, the present total effective root surface area, and the number of diseased teeth in order to predict the degree of decrease in the number of remaining teeth. A residual tooth prediction system that calculates a decrease curve of the total effective root surface area due to aging, wherein the total effective root surface area is the total area of the gingival-covered portion of the root surface of all remaining teeth. The number of lost teeth is the number of diseased teeth affected by dental caries and / or periodontal disease, and the number of lost teeth lost by dental caries and / or periodontal disease. Disease lost tooth number input means for inputting the number of teeth, current total effective root surface area calculation means for calculating the current total effective root surface area, and disease loss using the disease lost tooth number input by the disease lost tooth number input means Disease loss index from index calculation formula And disease loss index calculating means for calculating,
A storage means for storing a decrease curve calculation formula, a current age input by the age input means, the current total effective root surface area calculated by the current total effective root surface area calculation means, and the disease loss index calculation means Using the calculated disease loss index, processing means for obtaining the decrease curve by the decrease curve calculation formula stored in the storage means, and output means for outputting the decrease curve obtained by the processing means, It is characterized by having.

The remaining tooth prediction system according to the seventh aspect of the present invention calculates a remaining straight line of the total effective root surface area due to aging based on the current age and the current total effective root surface area in order to predict the degree of reduction of the remaining teeth. In the prediction system, the total effective root surface area is the total area of the portion covered by the gingiva among the root surfaces of all remaining teeth, and the age input means for inputting the current age and the current total effective root surface area are Current total effective root surface area calculating means for calculating, and storing means for storing a decreasing straight line calculating formula,
Using the current age input by the age input means and the current total effective root surface area calculated by the current total effective root surface area calculation means, the decrease is calculated by the decrease straight line calculation formula stored in the storage means. It is characterized by comprising processing means for obtaining a straight line, and output means for outputting the decreasing straight line obtained by the processing means.

[0008] The present remaining tooth prediction system includes a "current age"
A more accurate decrease curve can be calculated based on the "current total effective root surface area" and the "number of lost teeth". In addition, by using only the “current age” and the “current total effective root surface area”, it is possible to calculate a decrease straight line that is less accurate than the decrease curve but can be easily calculated.

In the present remaining tooth prediction system, the formula for calculating the current total effective root surface area, the formula for calculating the decreasing straight line, and the formula for calculating the decreasing straight line can be arbitrarily set. Further, as shown in the second invention as an example of each equation, the above-mentioned equation for calculating the decreasing curve is expressed by the above equation
And the formula for calculating the disease loss index can be the formula (3) described in the above equation (2). The constants G and m in the equation (1) are the variables TESAR _x and x in the equation (1).
Can be obtained by solving two simultaneous equations as the “non-regression total effective root surface area” and “non-regression age”, and the current total effective root surface area and current age, respectively. Furthermore,
As shown in the eighth invention, the equation for calculating the decreasing straight line can be the equation (9) described in the above equation (4).

Further, in the present remaining tooth prediction system, as shown in the third and ninth inventions, the non-regression total effective root surface area can be 7616 mm ² , and the non-retraction age can be 3.91 years. Note that these constants are values when gingival retraction does not occur, which is calculated by taking statistics of the current total effective root surface area and current age obtained from a large number of subjects, and these values are only used. It is not limited to.

In the present remaining tooth prediction system, as described in the fourth and tenth aspects, the present total effective root surface area calculating means includes tooth information input means for inputting the type and attachment level of each tooth of the remaining teeth. Effective root surface area calculation formula storage means for storing the effective root surface area calculation formulas of the following formulas (8) and (10) for each type of tooth, and the type and attachment level of each tooth input from the tooth information input means And calculating the effective root surface area from the effective root surface area calculation formula stored in the effective root surface area calculation formula storage means, and then calculating the current total effective root surface area which is the sum of the effective root surface areas of the respective teeth. Means for calculating total effective root surface area;
Effective root surface area sending means for sending the current total effective root surface area calculated by the current total effective root surface area calculating means to the processing means, wherein the attachment level is between the cement enamel boundary of the tooth, the bottom of the periodontal pocket and The height difference can be determined as follows.

In the present remaining tooth prediction system, as shown in the fifth and eleventh inventions, the attachment level is determined by the difference in height between the cement enamel boundary of the tooth and the gingival peak,
And the sum of the height difference between the gingival vertex and the bottom of the periodontal pocket, the height difference between the cement enamel boundary and the gingival vertex is 0 mm, 0.5 when the measured value of the height difference is less than 0.5 mm.
1 mm for 1 mm or more and less than 3 mm, 3 mm for 3 mm or more and less than 5 mm, 5 mm for 5 mm or more and less than 7 mm, 9 mm for 7 mm or more and less than 9 mm, 9 mm for 7 mm or more and less than 9 mm The height difference between the gingival apex and the bottom of the periodontal pocket is 0 mm when the measured value of the height difference is less than 2 mm.
mm 2 mm or more and less than 4 mm, 2 mm; 4 mm or more and less than 6 mm, 5 mm;
9mm if less than 0mm, 12mm if more than 10mm,
The value can be corrected.

As shown in a sixth aspect of the present residual tooth prediction system, the output means can output a reference decrease curve as a comparative example together with the decrease curve.
Further, as shown in an eleventh aspect of the present residual tooth prediction system, the output means can output a reference decrease straight line as a comparative example together with the decrease straight line.

The "effective root surface area" is the area of the part of the tooth root surface of a tooth that is covered by the gingiva. The "total effective root surface area" is the sum of the effective root surface areas of the remaining teeth as described in the first and sixth aspects. Further, the "current total effective root surface area" is the total effective root surface area at the time of measurement. The “current age” is the age at the time of measurement.

The above-mentioned "decrease curve" is a curve in which "current age", "current total effective root surface area" and "disease loss index" are variables. Generally, as the age increases, the total effective root area decreases. . Such a curve has an S-shaped shape, which gradually decreases in young people, but largely decreases in about forties, and thereafter decreases gradually again. The “disease loss index” is an index for taking into account the factors of diseased teeth and lost teeth, and decreases as the number of diseased teeth and lost teeth due to periodontal disease and dental caries increases. This index is usually 0.64
As described above, the value is less than 1. The “decrease straight line” is a straight line using “current age” and “current total effective root surface area” as variables, and generally, the total effective root surface area decreases as the age increases.

The "non-retraction" state is a healthy state in which the gingiva has not regressed from a normal position due to periodontal disease or the like, and the "non-regression age" and the "non-retraction total effective root surface area". Is the age at non-retraction and the total effective root surface area, respectively. The “current non-retraction total effective root surface area” is the total effective root surface area obtained by subtracting the effective root surface area at the time of non-retraction from the non-retraction total effective root surface area by the diseased tooth and the lost tooth.

Since it is difficult to measure the effective root surface area directly, the attachment level that can be easily measured is substituted into the effective root surface area calculation formula shown in the fourth and tenth aspects of the invention to calculate the effective root surface area. The "attachment level" is the height difference between the cement enamel boundary of the tooth and the bottom of the periodontal pocket, as shown in the fourth and tenth inventions. More specifically, as shown in the fifth and eleventh inventions, the sum of the height difference between the cement enamel boundary of the tooth and the gingival top and the height difference between the gingival top and the bottom of the periodontal pocket. The method of measuring the attachment level can be arbitrarily selected, and for example, measurement by a pocket probe can be mentioned.

The “reference decrease curve” and “reference decrease straight line” may be any curve or straight line indicating the degree of reduction of the total effective root surface area as an index of prevention and treatment, and may be any curve and straight line assuming arbitrary conditions. It can be. An example of this is the decrease curve and the decrease straight line of the total effective root surface area where 20 teeth remain at the age of 80 as exemplified by the 8020 exercise. Further, a decrease curve and a decrease straight line in a state where there are no remaining teeth at the age of 80 (the total effective root surface area is zero), a decrease curve and a decrease straight line in which 28 teeth remain at the age of 70 and the like can also be illustrated.

[Operation] The present remaining tooth prediction system uses the effective root surface area as an index of the number of remaining teeth, and predicts the degree of decrease in the number of remaining teeth based on the degree of decrease in the effective root surface area. In addition, the present remaining tooth prediction system does not target a specific remaining number of teeth. As an example of this,
Even when 28 unhealthy teeth remain and 19 healthy teeth remain, the same degree of reduction can be considered.

As a method of predicting the degree of decrease in the number of remaining teeth,
The number of remaining teeth at the current age may provide a way to predict future loss. However, the state of the currently remaining teeth (for example, a healthy state, a state of mild periodontal disease, a state of being severely falling out, etc.) varies greatly. In particular, the older the elderly, the more often they suffer from periodontal disease, and depending on the state of periodontal disease, the teeth easily fall off, and the degree of reduction in the number of teeth changes greatly. This periodontal disease is shown in FIG.
As shown in the figure, as the disease progresses, periodontal pockets are formed, alveolar bone is absorbed, and gingiva regresses and detaches from the root (decreased effective root surface area). It becomes easy to fall out.

The present invention focuses on the fact that the effective root surface area is reduced to make it easier for the teeth to come off. By investigating the total root area of various effective ages, the total root area is related to age. I found something. That is, it has been found that it can be approximated to a straight line using the total effective root surface area and age as variables. In addition, it was found that the effective root surface area without regression in a state in which gingival retraction did not occur can be determined by a statistical method based on many measured values because the root surface area matches the anatomical root surface area.

Based on this result, the degree of decrease in the number of remaining teeth was determined by calculating the total effective root surface area of the remaining teeth. Further, by expressing the degree of decrease in the number of remaining teeth by the total effective root surface area, a complicated intraoral state can be simplified, and the degree of decrease in the number of remaining teeth in the future can be easily predicted. Furthermore, by investigating whether or not the missing tooth has periodontal disease, and using the results of the investigation, the function of the total effective root surface area due to aging can be reduced to an S-shaped shape closer to the actual decrease tendency. It was found that it could be approximated to a shape curve.

As described above, according to the present invention, a decrease curve or a decrease straight line of the total effective root surface area in the future is obtained by using the already known average value of the anatomical root surface area and the indefinite age determined separately. , The degree of decrease in the number of remaining teeth in the future can be output. As a comparative example, for example, 8020
By exemplifying a decrease curve or a decrease straight line of the total effective root surface area, which is a target of exercise, such as 20 at the age of 80, it is possible to present prevention and treatment indexes and the like.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a remaining tooth prediction system according to the present invention will be described below with reference to FIGS. First, various calculation formulas required for the present remaining tooth prediction system were determined by the following method. (1) Calculation of the decrease line formula from the epidemiological survey of age and effective root surface area First, the following survey was performed to find the correlation between age and total effective root surface area to determine the decrease straight line and the function of the decrease curve. went. A random sample was taken from 172 subjects from the age of 20 to 85 years, and the subject's current age and current total effective root surface area were investigated. The results as shown in Table 1 and FIG. I asked. In addition, the present total effective root surface area was obtained by measuring the effective root surface area of each tooth by the same measuring method as the following (3) calculating method of the present total effective root surface area, and calculating the total.

[0025]

[Table 1]

Further, from the results shown in Table 1 and FIG. 5, the correlation coefficient between the effective root surface area and age could be approximated to a straight line of about -0.90. Further, in FIG.
It can be considered as an S-shaped curve that sharply decreases with age and gradually decreases after about 75 years old. Such a curve could be approximated by the equation (1) shown in Expression 1.

The variable used in equation (1) is
The disease loss index α is a coefficient representing the degree of decrease in the effective root surface area. The larger the value, the smaller the degree of decrease, and the smaller the value, the greater the degree of decrease. The reason why the disease loss index α obtained from the converted value _Rx and _{R0 of the} number of diseased teeth is used for calculating the degree of decrease in the total effective root surface area will be described below. In other words, reasons for losing teeth include accidents and diseases.
Among them, diseases, particularly diseases and loss due to periodontal disease and dental caries, are factors that can be considered to be more likely to deteriorate periodontal disease and dental caries of other non-losing teeth. That is, usually, the total effective root surface area decreases in accordance with the degree of progression of periodontal disease (see FIG. 6). However, when teeth are lost due to severe periodontal disease or dental caries, the total effective root surface area is apparently improved because the total effective root surface area does not decrease due to the lost teeth. Even with this apparent improvement, the actual progression of periodontal disease and dental caries often does not change significantly. Therefore, using the disease loss index α, the degree of decrease in the total effective root surface area that was present is calculated. Things.

The disease loss index α can be obtained from the state of periodontal disease or dental caries and the number of missing teeth. For example, when the patient is not affected by periodontal disease or dental caries (α is a large value 7) can be a curve that can be approximated to a straight line as indicated by L1 in FIG. 7, and if many teeth are affected by periodontal disease or dental caries (when α is a small value) .) Can be an S-shaped curve as indicated by L2 in FIG. This disease loss index α was obtained by formula (3) shown in Expression 2 by finding a formula that matches the data of the 1993 Dental Disease Survey Report. The range of α that can be calculated from the equation (3) is usually about 0.64 or more and less than 1. In other words, there is a range between α ≒ 0.64 at which all teeth are lost in the early 30 years and the teeth become edentulous, and α = 1 at which the effective root surface area does not decrease.

Further, (3) Rrate in formula, see the disease Loss of teeth converted value R _x of the actual measurement, in the ratio (the number 2 of the average disease Loss of teeth converted value R _o (4) below. If it is less than 1, it means that the measured value of the number of lost teeth is smaller than the average value of the number of lost teeth. Furthermore, the disease lost teeth converted value R _x and diseases number of missing teeth converted value R _o of the actual measurement of the actual measurement, the in each number 2 (5) and (6). Note that 30 in the equations (5) and (6) is a constant experimentally determined to increase the weight of the number M of missing teeth.

The degree of decrease in tooth support tissue γ in equation (1) in equation (1) corrects the apparent improvement in periodontal disease due to tooth extraction. In other words, as the periodontal disease progresses, the gingiva may retreat until the root cannot be supported, and tooth extraction may be required. In addition, since the root of the tooth extraction portion is not measured, it appears that the disease state has been improved. For this reason,
Degree of decrease in tooth support tissue as shown in equation (2) in equation (1)
By performing the correction, the total effective root surface area closer to the actual state can be calculated.

Further, since the constants G and m in the expression (1) in Equation 1 have values peculiar to the subject, they cannot be uniquely determined. Therefore, the variable TESAR _{x in} equation (1)
And x are the non-retraction total effective root surface area TASAR, respectively
And age of non-regression m ₀ , and current total effective root surface area NTE
Found by solving the SAR and simultaneous equations of two formulas that the current age x _0.

(2) Determination of Non-Retraction Point The non-retraction total effective root surface area and the non-retraction age indicating the non-retraction point were obtained as follows. Non-retraction total effective root surface area is the sum of the anatomical root surface areas of each tooth. Since the anatomical root surface area of each tooth is already known as a result of the study on the anatomical root surface area of each tooth type by Tylman & Malone shown in Table 2, it is possible to obtain about 761
It was determined to be 6 mm ² .

[0033]

[Table 2]

The non-regression age is (1) the total effective root surface area of the approximate straight line obtained by calculating the decreasing line equation from the epidemiological survey of the age and the effective root surface area is the non-regression total effective root surface area. It was found that the age at the time when it was about 7,616 mm ² was about 3.91 years.

(3) Method of Calculating the Current Total Effective Root Surface Area The current total effective root surface area obtained by the current total effective root surface area calculating means was obtained by the following method. Determination of Attachment Level Measurement Teeth There are a total of 32 human teeth, and it takes time to measure the attachment level required to calculate the current total effective root surface area for all of them. For this reason, in order to shorten the measurement time and reduce the burden on the subject, several teeth that often have similar conditions of periodontal disease are taken as one set, and only one of the set is measured. did. In addition, the third molar T8 shown in FIG.
(Also known as wisdom teeth) was excluded from the total effective root surface area because some or all of them did not grow.

Specifically, of the 28 teeth except for the third molars 8, six teeth shown in FIG. 4 and Table 3 were selected and measured. In addition, the effective root surface area of the tooth for which the measurement was not performed was replaced with the tooth measurement value shown in Table 3. That is, as shown in Table 3 and FIG.
1, the side incisor T2 and the canine T3 are replaced by the measured value of the central incisor T1, and the first premolar T4, the second premolar T5, and the second molar T7 are replaced by the first molar T6. Substituted with measured values.

[0037]

[Table 3]

Measurement of Attachment Level The measurement site of the attachment level in each individual tooth is:
Six points around the tooth, which are measurement sites generally used for measuring periodontal pockets (see M1 to M6 shown in FIG. 4).
Was measured. Among them, the value of a specific measurement point was used for each tooth type.

As shown in FIGS. 2 and 3, the attachment level C was measured by measuring the gingival retraction value A, which is the height difference between the cement enamel boundary of the tooth and the gingival vertex, and the gingival vertex and the bottom of the periodontal pocket. Periodontal pocket value B, which is the height difference, 2
The measurement was performed using a pocket probe.

Correction of Measured Value In the above-mentioned measurement of the attachment level, the measurement using the pocket probe tends to cause an error of about 1 mm. For this reason, the attachment level C is measured separately for the periodontal pocket value B and the gingival regression value A, and the measured values are stepwise converted using the conversion tables shown in Tables 4 and 5, respectively. The value was used to correct the error.

[0041]

[Table 4]

[0042]

[Table 5]

The conversion table of periodontal pocket values shown in Table 4 is shown in FIG. 2 in order to reduce errors due to pseudo periodontal pockets 96 which are likely to occur in young people in their 20s.
The evaluation is more detailed than the gingival regression value shown in FIG.

Correction of Non-Retraction Effective Root Surface Area by Age A curve of the total effective root surface area can be calculated using the corrected non-retraction effective root surface area. That is, shown in Equation 3
When the effective root surface area is calculated using Expression (8) and Expression (10) shown in Equation 5, the effective root surface area tends to become larger as the current age increases. In order to cope with this, the non-retraction effective root surface area is corrected by using the equation (11) shown in the equation (6), and the obtained corrected current non-retraction effective root surface area RNTASAR is converted to the current non-regression in the equation (2) of the equation The effective root surface area was calculated by substituting into the effective root surface area NTASAR.

(Equation 6)

Correction of Congenital Lack of Teeth Some of the persons to be measured do not have a natural number of teeth of 28 due to the congenital lack of teeth other than the third molars 8. This congenital defect is caused by the third molar T8 shown in FIG.
In addition, the central incisor T1 of the lower jaw, the lateral incisor T2 of the upper jaw, and the second premolar T5 of the upper and lower jaw are many, and the expression rate excluding the third molar T8 is 2-3%. The total effective root surface area without regression in consideration of the decrease in the effective root surface area due to the lack of birth is about 7181 mm ² .

Therefore, the total effective root surface area obtained based on the measurement was corrected by multiplying the total effective root surface area by a congenital lack correction coefficient in order to compensate for the decrease due to lack of birth. The congenital deficiency correction coefficient is (non-regression total effective root surface area without congenital deficiency) / (non-regression total effective root surface area in consideration of congenital deficiency) = 7616/7181 ≒ 1.06
It becomes 1. This birth defect correction coefficient is multiplied by the calculated effective root surface area and the number of missing teeth.

Calculation of Current Total Effective Root Surface Area Based on the above contents, the current total effective root surface area was calculated according to the following procedure. First, the tooth selected in the determination of the attachment level measurement tooth was determined for the corrected gingival retraction value and the corrected periodontal pocket value of each tooth and each point by the method shown in the attachment level measurement.

Next, the measured corrected gingival retraction value and corrected periodontal pocket value were corrected by the correction of the measured values to obtain the corrected gingival retraction value and corrected periodontal pocket value, respectively. Thereafter, the sum of the corrected gingival retraction value and the corrected periodontal pocket value at the measurement points M1 to M6 of each tooth is obtained,
The average value was taken as the attachment level of each tooth.

Next, the attachment level of each tooth,
Anatomical root surface area and anatomical root length shown in Table 2,
The non-retraction effective root surface area calculated by correcting the non-retraction effective root surface area according to age was substituted into Expression (8) shown in Expression 3 to obtain the effective root surface area of each tooth. Thereafter, the value of the effective root surface area of the tooth determined by the determination of the measurement tooth at the attachment level was applied to the effective root surface area of the tooth that had not been measured, and the total effective root surface area of the front teeth was determined. Next, this total value was multiplied by a birth defect correction coefficient (1.061), which is a correction for the birth defect teeth, to obtain the current total effective root surface area.

(4) Calculation Method of Curve and Reduction Line of Total Effective Root Surface Area First, the variables TESAR _x and x in the equation (1) shown in Equation 1 are respectively set to the non-regression total effective root surface area TASAR and the non-retraction. By solving two simultaneous equations with the age m ₀ , the current total effective root surface area NTESAR and the current age x ₀ , (1)
Determine the constants G and m in the equation. Then, the current total effective root surface area, the non-regression age, the disease loss index and the non-regression total effective root surface area obtained by the above (2) determination of the no-retraction point and (3) calculation method of the current total effective root surface area By substituting various constants such as the current age and the like into the equation (1) shown in Expression 1, a curve of the total effective root surface area can be calculated. Also, by substituting the current total effective root surface area, the non-regressive age, and the non-regressive total effective root surface area, and the current age into equation (9) shown in Equation 4,
A straight line of the total effective root surface area can be calculated.

(5) Calculation method of reference decrease curve and reference decrease straight line In calculation of the reference decrease curve and reference decrease straight line, the reference current age and the present total effective root surface area are determined. The reference decrease curve and the reference decrease straight line can be calculated by using the method of calculating the decrease straight line of the root surface area. For example, in order to calculate a decrease line of the total effective root surface area which becomes 20 at the age of 80, the current age is assumed to be 80 years, and the current total effective root surface area is calculated assuming that there are remaining teeth as shown below. By setting the effective root surface area to 3150 mm ² , a decrease straight line can be calculated. That is, the remaining teeth are the left and right upper and lower jaw central incisors T1, lateral incisors T2, canines T3,
The first premolar T4 and the second premolar T5, each of which is assumed to remain in a healthy state, the total effective root surface area is determined, and a reference decreasing straight line can be calculated.

[0052]

[Embodiment 1] A remaining tooth prediction system for predicting the degree of reduction of remaining teeth based on the above results and outputting a reduction curve will be described below. (1) Configuration of the remaining tooth prediction system The present remaining tooth prediction system includes an input device 1 as shown in FIG.
, A storage device 2, a processing device 3, a CRT display 41, and a printer 42.

Hereinafter, each component of the remaining tooth prediction system will be described. Input Device 1 The input device 1, which is a tooth information input unit 1a, an age input unit 1b, and a diseased tooth count input unit 1c, is configured by a keyboard or the like, and includes a current age of a subject, a measured gingival regression value, The periodontal pocket value, the number of missing teeth, the number of diseased teeth, and the like are input. These pieces of information are output to the processing device 3.

Storage device 2 Storage device 2 serving as storage means 2a, effective root surface area calculation formula storage means 2b, and disease loss index calculation formula storage means 2c.
Consists of a magnetic disk, IC memory, etc.
In addition to the reduction curve calculation formula, the effective root surface area calculation formula, and the disease loss index calculation formula required for the arithmetic processing in the processing device 3, the constant non-regression total effective root surface area, which is a constant required for these formulas,
The age of non-regression and the anatomical root surface area and anatomical root length for each tooth type are stored. Further, a conversion table for performing periodontal pocket values and gingival retraction values shown in Tables 4 and 5, a birth defect correction coefficient, and the like are also stored. These are output to the processing device 3.

Processing Unit 3 The processing unit 3, which is the processing unit 3c, the disease loss index calculating unit 3b, and the current total effective root surface area calculating unit 3a, comprises a personal computer, a workstation, a microcomputer, and the like. This processing device 3
The current age of the subject and the measured gingival regression value and periodontal pocket value input by the input device 1 are stored in the storage device 2.
Receives the effective root surface area calculation formula and the like stored in the above, and calculates the current total effective root surface area. Further, the disease loss index is calculated using the number of diseased teeth and the number of missing teeth of the subject input by the input device 1 and the disease loss index calculation formula stored in the storage unit 2. Further, it receives the current age of the person to be measured input by the input device 1, the equation for calculating the decrease curve stored in the storage means 2, and the current total effective root surface area calculated in the processing device 3. Is calculated.

CRT display 41 and printer 4
(2) The CRT display 41 and the printer 42, which are the output means 4a, receive the decreasing curve as a result from the processing device 3 and display it as a graph on the CRT display 41 or print it on the printer 42. Further, a reference decrease curve serving as a comparative example is superimposed and printed with a decrease curve of the total effective root surface area.

(2) Processing in the residual tooth prediction system The residual tooth prediction system having the above configuration calculates a decrease curve of the total effective root surface area by the following procedure. First, the current age of the subject, the corrected gingival retraction value and corrected periodontal pocket value of each point of each tooth, the number of diseased teeth and the number of missing teeth are input to the input device 1. These input various values are sent to the processing device 3.

Next, the processing device 3 calculates the corrected gingival regression value and the corrected periodontal pocket value of each point of each tooth input by the input device 1 and the effective root surface area calculation formula stored in the storage device 2, Processing is performed based on the anatomical root surface area and the anatomical root length for each tooth type, and the effective root surface area of each tooth is calculated. Also, the number of diseased teeth and the number of missing teeth,
Processing is performed based on the disease loss index calculating means 3b and the like stored in the storage device 2, and the disease loss index is calculated.

After that, the processing device 3 calculates the current age input by the input device 1, the decreasing curve calculation formula stored in the storage device 2, the total effective root surface area without involution, the disease loss index,
Then, the process is performed based on the non-regressive age and the effective root surface area of each tooth in the processing device 3 to calculate a decrease curve of the total effective root surface area. The decrease curve of the total effective root surface area is sent to the CRT display 41 and the printer 42 as the output means 4a together with the reference decrease curve in which 20 teeth remain at the age of 80 as a comparative example. The 20 teeth were the left and right upper and lower jaw central incisors T1, lateral incisors T2, canines T3, first premolars T4, and second premolars T5.

Next, the CRT display 41 receives the decrease curve of the total effective root surface area and the reference decrease curve from the processing device 3 and displays them in a superimposed state. Also,
Similarly, the printer 42 performs printing in a state where the decrease curve of the total effective root surface area and the reference decrease curve are superimposed.

(3) Effect of the remaining tooth prediction system FIG. 1 shows an example of a reduction curve of the total effective root surface area obtained by the present remaining tooth prediction system. The decrease curve of the total effective root surface area is for a subject whose current age is 56 years old and whose total effective root surface area is about 270.96 mm ² . As shown in FIG. 1, in this subject, if the current oral management is continued, the total effective root surface area at the age of 80 is about 200.
mm ² , and it can be seen that 20 healthy remaining teeth cannot be maintained when compared with the reference decrease curve in which 20 remaining teeth remain at the age of 80. By using this result in a way such as presenting it to the person being measured,
For example, to be able to maintain 20 remaining teeth at the age of 80,
Guidance on appropriate oral management can be easily provided.

As shown in this example, the present residual tooth prediction system outputs a decrease curve of the total effective root surface area, so that it is possible to predict the number of remaining teeth which is easy to understand, and to prevent long-term teeth. It can be used as a material for performing treatment and guidance. In addition, the reduction curve of the total effective root surface area can be obtained using the non-destructive and easily measurable value of the attachment level, making the present remaining tooth prediction system easily usable and a long-term tooth Can be easily provided as a material for prevention, treatment and guidance.

[Embodiment 2] A remaining tooth prediction system for predicting the degree of reduction of remaining teeth and outputting a reduction straight line will be described below. (1) Configuration of Remaining Tooth Prediction System The present remaining tooth prediction system includes an input device 1, a storage device 2, a processing device 3, a CRT display 41, and a printer 42, as shown in FIG.

Hereinafter, each component of the remaining tooth prediction system will be described. Input device 1 The input device 1 serving as the tooth information input means 1a and the age input means 1b is constituted by a keyboard or the like, and inputs the current age of the subject, and the measured gingival regression value and periodontal pocket value. . These pieces of information are output to the processing device 3.

Storage device 2 Storage means 2a and effective root surface area calculation formula storage means 2b
The storage device 2 is composed of a magnetic disk, an IC memory, and the like. In addition to the reduced straight line calculation formula, the effective root surface area calculation formula, and the disease loss index calculation formula necessary for the arithmetic processing in the processing device 3, Are stored as constants necessary for the formula (1), such as the total non-regressive effective root surface area, the non-regression age, the anatomical root surface area and the anatomical root length for each tooth type. Further, a conversion table for performing periodontal pocket values and gingival retraction values shown in Tables 4 and 5, a birth defect correction coefficient, and the like are also stored. These are output to the processing device 3.

Processing Unit 3 The processing unit 3c as the processing unit 3c and the processing unit 3 as the present total effective root surface area calculating unit 3a are constituted by a personal computer, a workstation, a microcomputer or the like. The processing device 3 receives the current age of the subject and the measured gingival regression value and periodontal pocket value input by the input device 1 and receives an effective root surface area calculation formula and the like stored in the storage device 2, Calculate the current total effective root surface area.
Further, it receives the current age of the person to be measured input by the input device 1, the equation for calculating the decreasing straight line stored in the storage means 2, and the current total effective root surface area calculated in the processing device 3. Is calculated.

CRT display 41 and printer 4
(2) The CRT display 41 and the printer 42, which are the output means 4a, receive the decreasing straight line as a result from the processing device 3, and display the graph on the CRT display 41 or print the graph by the printer 42. In addition, a reference decreasing straight line as a comparative example is printed while being superimposed on a decreasing straight line of the total effective root surface area.

(2) Processing in the residual tooth prediction system The residual tooth prediction system having the above configuration calculates a straight line for decreasing the total effective root surface area by the following procedure. First, the current age of the subject and the corrected gingival retraction value and the corrected periodontal pocket value of each point of each tooth are input to the input device 1. These input various values are sent to the processing device 3.

Next, the processing device 3 calculates the corrected gingival regression value and the corrected periodontal pocket value of each point of each tooth input by the input device 1 and the effective root surface area calculation formula stored in the storage device 2, Processing is performed based on the anatomical root surface area and the anatomical root length for each tooth type, and the effective root surface area of each tooth is calculated.

Thereafter, the processing device 3 calculates the current age input by the input device 1, the reduced straight line calculation formula stored in the storage device 2, the non-retraction total effective root surface area, and the non-regression age. The processing is performed based on the effective root surface area of each tooth within, and a decrease straight line of the total effective root surface area is calculated. The reduced straight line of the total effective root surface area is sent to the CRT display 41 and the printer 42, which are the output means 4a, together with the reference reduced straight line in which 20 teeth remain at the age of 80 as a comparative example. The 20 teeth were the left and right upper and lower jaw central incisors T1, lateral incisors T2, canines T3, first premolars T4, and second premolars T5.

Next, the CRT display 41 receives the decreasing line of the total effective root surface area and the reference decreasing line from the processing device 3 and displays them in a superimposed state. Also,
Similarly, the printer 42 performs printing in a state where the reduction line of the total effective root surface area and the reference reduction line are overlapped.

(3) Effects of the remaining tooth prediction system FIG. 9 shows an example of a straight line for decreasing the total effective root surface area obtained by the present remaining tooth prediction system. This straight line of the total effective root surface area shows that the current age is 57 years old and the total effective root surface area is 3
589.15 mm ² of the person to be measured. As shown in FIG. 9, in this subject, if the current oral cavity management is continued, the total effective root surface area at the age of 80 is about 1800.
mm ² , which indicates that it is not possible to maintain 20 healthy remaining teeth when compared with the reference decrease straight line in which 20 remaining teeth remain at the age of 80. By using this result in a way such as presenting it to the person being measured,
For example, to be able to maintain 20 remaining teeth at the age of 80,
Guidance on appropriate oral management can be easily provided.

The present residual tooth prediction system outputs a straight line of decrease in the total effective root surface area, so that it is possible to predict the number of remaining teeth that is easy to understand, and to perform long-term prevention, treatment and guidance of teeth. It can be used as a reference material. In addition, the present remaining tooth prediction system outputs a decreasing straight line with lower accuracy than the remaining tooth prediction system shown in the first embodiment, but inputs the number of diseased teeth and the number of missing teeth necessary for obtaining the disease loss index. No need. Therefore, the measurement time for the person to be measured can be reduced, the burden on the person to be measured is small, and the result can be obtained in a short time.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention according to the purpose and application. That is, the number of teeth for which the attachment level was measured in the embodiment is only six out of a total of 28 teeth excluding the third molar T8, but the number of measurement targets may be increased to 8, 20, or the like. , Can also be applied to all teeth. By increasing the measurement target as shown in these,
Although the measurement time increases, a more accurate decrease curve of the total effective root surface area can be obtained. Further, in the case of a simpler survey, the number of measurement objects can be reduced to four or the like, and the measurement time can be shortened.

Instead of reducing the number of measurement points of one tooth, the number of teeth to be measured may be increased. Alternatively, the reverse may be performed. In addition, when the number of measurement targets is reduced, an error increases if the gingival state is greatly different for each tooth. Therefore, when the state of each tooth is different, increasing the number of measurement targets and measuring reduces the error. It is preferred because it can be.

The output means 4a, such as the CRT display 41 and the printer 42, outputs a result when outputting the results. Can be output together. Further, an achievement index indicating how much the 8020 exercise can be achieved as described in the technical field to which the invention pertains can be output together.

The formulas for calculating the decreasing curve and the decreasing straight line are as follows:
The formula is not limited to the formula shown in each embodiment. For example, the equation for calculating the decrease curve can be the equation (12) shown in Equation 7. This (12)
By uniquely determining the constants α, G, and m in the equation in advance,
The constant k can be easily determined. That is, the variables TESAR _x and x in equation (12) are replaced by the current total effective root surface area NT.
The constant k can be determined by the ESAR and the current age x _0. In addition, the constants α, G, and m can be obtained as statistical values by using statistical materials (for example, results of a dental disease survey) that have been investigated in advance. Also in the thus obtained decrease curve equation, a decrease curve that can be sufficiently used for predicting the degree of decrease of the remaining teeth can be obtained.

[0078]

(Equation 7)

Further, the remaining tooth prediction system of the first embodiment can also output a decreasing straight line instead of the decreasing curve without calculating the disease loss index. When the disease loss index is not calculated as described above, only a decrease straight line less accurate than the decrease curve is obtained, but the result can be output without investigating the disease lost tooth. For this reason, the time required to investigate missing teeth can be shortened,
The remaining tooth prediction system can obtain a result in a short time.

Further, by using each method shown in the embodiment, it is possible to calculate a decrease curve and a decrease straight line of the total effective root surface area. However, when comparing the obtained decrease curve and the decrease line with the decrease curve and the decrease line obtained by actually conducting the investigation, differences are found in details. To cope with this, various corrections can be made to obtain a more realistic reduction line.

[0081]

According to the residual tooth prediction system of the first invention, a decrease curve of the total effective root surface area can be calculated based on the current age, the current total effective root surface area, and the number of diseased teeth. The degree of decrease in the number of remaining teeth is predicted based on the decrease curve of the total effective root surface area, and can be used as data for long-term prevention, treatment and guidance of teeth.

The reduction curve can be calculated using the reduction curve calculation formula and the disease loss index calculation formula shown in the second invention, and the non-regression total effective root surface area and the non-regression age shown in the third invention. . In the remaining tooth prediction system according to the fourth aspect of the present invention, the total effective root surface area is determined based on the type and the attachment level of each tooth of the remaining teeth, so that a decrease curve of the total effective root surface area can be easily calculated.

In the remaining tooth prediction system according to the fifth aspect of the present invention, the attachment level is set to a stepwise value,
The error in the decrease curve of the total effective root surface area can be reduced. In the remaining tooth prediction system according to the sixth aspect of the present invention, by outputting a reference decrease curve as a comparative example together with the decrease curve, usability can be improved as data.

In the remaining tooth prediction system according to the seventh aspect of the present invention, a straight line for decreasing the total effective root surface area can be calculated based on the current age and the current total effective root surface area. Predict the degree of decrease in the number of remaining teeth
It can be used as a material for long-term prevention, treatment and guidance of teeth.

Further, this decrease curve can be calculated using the decrease curve calculation formula shown in the eighth invention, and the non-regression total effective root surface area and the non-regression age shown in the ninth invention. In the remaining tooth prediction system according to the tenth aspect of the present invention, the total effective root surface area is determined based on the type and attachment level of each tooth of the remaining teeth, so that a straight line for decreasing the total effective root surface area can be easily calculated.

In the remaining tooth prediction system according to the eleventh aspect of the present invention, the error of the straight line of the total effective root surface area can be reduced by setting the attachment level to a stepwise value. In the remaining tooth prediction system according to the twelfth aspect of the invention, by outputting a reference decrease straight line as a comparative example together with the decrease straight line, usability can be improved as a material.

[Brief description of the drawings]

FIG. 1 is a graph showing an example of a decrease curve of the total effective root surface area.

FIG. 2 is a schematic cross-sectional view illustrating a tooth on which a pseudo periodontal pocket is formed.

FIG. 3 is a schematic cross-sectional view for explaining a tooth having a periodontal pocket formed due to periodontal disease.

FIG. 4 is a schematic diagram for explaining an arrangement of teeth and measurement positions of attachment levels.

FIG. 5 is a graph obtained from random extraction from the age of 20 to 85 years and the age and the total effective root surface area.

FIG. 6 is a graph showing how the number of remaining teeth and the total effective root surface area decrease with aging. This graph was created based on the data of the 1993 Dental Disease Survey.

FIG. 7 is a graph showing a state of a change in a decrease curve according to a disease loss index.

FIG. 8 is an explanatory diagram of each component of the present remaining tooth prediction system.

FIG. 9 is a graph showing an example of a straight line for decreasing the total effective root surface area.

FIG. 10 is an explanatory diagram of each component of the present remaining tooth prediction system.

[Explanation of symbols]

Reference Signs List 1: input device, 1a; tooth information input means, 1b; age input means, 1c; disease lost tooth number input means, 2: storage device, 2
a: storage means, 2b: effective root surface area calculation formula storage means,
2c; disease loss index calculation formula storage means, 3; processing device, 3
a: current total effective root surface area calculating means, 3b; disease loss index calculating means, 3c; processing means, 41; CRT display, 42; printer, 4a; output means, 91;
2; crown, 93: cement enamel boundary, 94; gingiva, 9
5; periodontal pocket, 96; pseudo periodontal pocket, A: gingival retraction value, B: periodontal pocket value, C: attachment level, M1 to M6: measurement site, T1: central incisor, T2: lateral incisor, T3; canine, T4; first premolar, T5; second premolar, T6; first molar, T7; second molar, T8;
Molars.

Claims (12)

[Claims] 1. A residual tooth for calculating a decrease curve of the total effective root surface area due to aging based on at least the current age, the present total effective root surface area, and the number of disease-lossed teeth in order to predict the degree of reduction of the remaining tooth. A prediction system, wherein the total effective root surface area is a total area of a portion of the root surface of all remaining teeth that is covered with gingiva, and the number of disease-loss teeth is affected by caries and / or periodontal disease. An age inputting means for inputting the current age, a diseased toothlessness inputting means for inputting the number of diseased teeth, and a current total number of lost teeth lost due to caries and / or periodontal disease. Current total effective root surface area calculating means for calculating the effective root surface area, and a disease loss index calculating means for calculating a disease loss index from a disease loss index calculation formula using the number of disease lost teeth input by the number of disease lost teeth input means And the decrease curve calculation formula A current age input by the age input means, the current total effective root surface area calculated by the current total effective root surface area calculating means, and a disease calculated by the disease loss index calculating means. Processing means for obtaining the decrease curve by the decrease curve calculation formula stored in the storage means using the loss index; output means for outputting the decrease curve obtained by the processing means;
A remaining tooth prediction system, comprising: 2. The formula for calculating the decrease curve is the following formula (1), and the formula for calculating the disease loss index is the following formula (3).
The constants G and m in the equation (1) are the variables TESAR in the equation (1).
The remaining tooth prediction system according to claim 1, wherein _x and x are obtained by solving two simultaneous equations, where x is a total effective root surface area and a non-regressive age, and x is a current total effective root surface area and a current age. . (Equation 1) (Equation 2) 3. The non-retraction total effective root surface area is 7,616.
^3. The remaining tooth prediction system according to claim ² , wherein mm ² , and the age without involution is 3.91 years. The present total effective root surface area calculating means includes: tooth information input means for inputting the type and attachment level of each tooth of the remaining teeth; anatomical root length for each tooth type; Effective root surface area calculation formula storage means for storing an effective root surface area calculation equation, which is an expression, and the type and attachment level of each tooth input from the tooth information input means, and effective root surface area calculation formula storage means A current total effective root surface area calculating means for calculating the effective root surface area from the effective root surface area calculation formula, and thereafter calculating a current total effective root surface area which is a sum of the effective root surface areas of the respective teeth; Effective root surface area sending means for sending the current total effective root surface area determined by the surface area calculating means to the processing means, wherein the attachment level is a cement enamel boundary of the tooth, It is a height difference between the bottom of the pocket according to claim 1, 2 or 3 remaining teeth prediction system according. (Equation 3) 5. The attachment level is a sum of a height difference between a cement enamel boundary of a tooth and a gingival vertex and a height difference between a gingival vertex and a bottom of a periodontal pocket. The height difference is 0 mm when the measured value of the height difference is less than 0.5 mm, 1 mm when it is 0.5 mm or more and less than 1 mm, and 3 m when it is 1 mm or more and less than 3 mm.
m: 5mm when 3 or more and less than 5 7mm when 5mm or more and less than 7mm, 9mm when 7mm or more and less than 9mm, 10mm when 9mm or more, and the height difference between the gingival vertex and the bottom of the periodontal pocket 0 mm when the height difference is less than 2 mm, 2 mm when the height is 2 mm or more and less than 4 mm, 5 mm when the height difference is 4 mm or more and less than 6 mm, and 6 mm or more.
If it is less than 7 mm, it is 9 mm if it is 8 mm or more and less than 10 mm,
The remaining tooth prediction system according to claim 4, wherein when the distance is 10 mm or more, the distance is set to 12 mm. 6. The remaining tooth prediction system according to claim 1, wherein the output means outputs a reference decrease curve as a comparative example together with the decrease curve. 7. A remaining tooth prediction system for calculating a decrease straight line of the total effective root surface area due to aging based on the current age and the current total effective root surface area in order to predict the degree of reduction of the remaining teeth, The root surface area is the total area of the portion of the root surface of all remaining teeth covered by the gingiva. Age input means for inputting the current age, and current total effective root surface area calculation means for calculating the current total effective root surface area A storage means for storing a decreasing straight line calculation formula; a current age input by the age input means; and the current total effective root surface area calculated by the current total effective root surface area calculation means, and Processing means for obtaining the decreasing straight line by the decreasing straight line calculation formula stored in the means; output means for outputting the decreasing straight line obtained by the processing means;
A remaining tooth prediction system, comprising: 8. The remaining tooth prediction system according to claim 7, wherein the equation for calculating the decreasing straight line is an equation described in the following equation (9). (Equation 4) 9. The non-retraction total effective root surface area is 7,616.
mm ^2, the residual teeth prediction system according to claim 7 or 8, wherein said free retraction age and 3.91 years of age. 10. The current total effective root surface area calculating means,
Tooth information input means for inputting the type and attachment level of each tooth of the remaining teeth; effective root surface area calculation storing an anatomical root length for each tooth type and an effective root surface area calculation formula of the following formula (10) Formula storage means, the type and attachment level of each tooth inputted from the tooth information input means, and the effective root surface area calculation formula stored in the effective root surface area calculation formula storage means to calculate the effective root surface area, Current total effective root surface area calculation means for calculating a total current effective root surface area that is the sum of the effective root surface areas of the respective teeth; and processing the current total effective root surface area determined by the current total effective root surface area calculation means in the above-described processing. Means for delivering effective root surface area to said means, said attachment level being a height difference between the cement enamel boundary of the tooth and the bottom of the periodontal pocket. 9 remaining teeth prediction system according. (Equation 5) 11. The attachment level is a sum of a height difference between a cement enamel boundary of a tooth and a gingival vertex, and a height difference between a gingival vertex and a bottom of a periodontal pocket. The height difference is 0 mm when the measured value of the height difference is less than 0.5 mm, 1 mm when it is 0.5 mm or more and less than 1 mm, and 3 m when it is 1 mm or more and less than 3 mm.
m: 5mm when 3 or more and less than 5 7mm when 5mm or more and less than 7mm, 9mm when 7mm or more and less than 9mm, 10mm when 9mm or more, and the height difference between the gingival vertex and the bottom of the periodontal pocket 0 mm when the height difference is less than 2 mm, 2 mm when the height is 2 mm or more and less than 4 mm, 5 mm when the height difference is 4 mm or more and less than 6 mm, and 6 mm or more.
If it is less than 7 mm, it is 9 mm if it is 8 mm or more and less than 10 mm,
11. The remaining tooth prediction system according to claim 10, wherein when the distance is 10 mm or more, the distance is set to 12 mm. 12. The remaining tooth prediction system according to claim 7, wherein the output means outputs a reference decrease straight line as a comparative example together with the decrease straight line.