JP7414210B2 - Dental age calculation device and tooth age calculation program - Google Patents

Description

The present invention relates to a technique for calculating tooth age.

Tooth age is calculated by evaluating the degree of maturity of the tooth germs of all permanent teeth shown in a panoramic X-ray image. Dental age is one of the physiological ages and is used as an index to measure the growth of children. Because there are individual differences in the development of children and variations in the growth of tooth germs, it is often observed in daily clinical practice that tooth age and chronological age do not match.

By determining the tooth age, it is possible to make various diagnoses, such as evaluating whether the replacement of baby teeth with permanent teeth is early or slow, evaluating the left-right difference in the replacement of baby teeth with permanent teeth, and suspecting diseases. . For this reason, many people involved in pediatric dentistry calculate the age of teeth.

Haavikko, K. (1970). The formation and the alveolar and clinical eruption of the permanent teeth. Anorthopantomographic study. Suom Hammaslaak Toim 66, 103-170.

Although the method disclosed in Non-Patent Document 1 is often used to calculate tooth age, the calculation procedure is complicated and requires a lot of effort.

Further, even if a dentist who is unfamiliar with pediatric dentistry knows that tooth age is useful information, he or she may not know how to calculate tooth age.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a tooth age calculation device and a tooth age calculation program that automatically calculate tooth age.

In order to achieve the above object, a tooth age calculation device according to the present invention includes an acquisition section, a detection section, a determination section, a storage section, and a calculation section. The acquisition unit acquires a panoramic X-ray image of a child's tooth germ. The detection unit detects the type of tooth germ from the panoramic X-ray image using a first learning model obtained by causing a first artificial intelligence to learn in advance the relationship between the ROI (Region of Interest) and the type of tooth germ. To identify and detect tooth germs. The determining unit determines the developmental stage of each tooth germ detected by the detecting unit using a second learning model obtained by causing a second artificial intelligence to learn in advance the relationship between the shape of the tooth germ and the developmental stage. judge. The storage unit stores in advance reference values for each developmental stage of the tooth germ. The calculation unit calculates the tooth age of each tooth germ detected by the detection unit using the determination result of the determination unit and the reference value, and calculates the tooth age of each tooth germ detected by the detection unit from the tooth age of each tooth germ detected by the detection unit. Calculate a child's dental age.

In the tooth age calculation device having the above configuration, the determination unit determines the developmental stages to include a tooth germ formation period, a calcification initiation period, a crown formation period initiation period, and a 1/2 period of the tooth crown formation period. a first stage, a second stage including 3/4 stage of the tooth crown formation stage, a third stage including the completion stage of the tooth crown formation stage, a fourth stage including 1/4 stage of the tooth root formation stage, the tooth root 5th stage including 1/2 stage of the tooth formation stage, 6th stage including 3/4 stage of the root formation stage, 7th stage including the completion stage of the tooth root formation stage, and 8th stage including the apical closure stage. The developmental stages may be evaluated by dividing into stages. Moreover, in the tooth age calculation device having any of the above configurations, the determination unit may classify the tooth germ into two types, ie, front teeth or premolars and molars, and evaluate the developmental stage.

In order to achieve the above object, the tooth age calculation program according to the present invention causes a computer to function as an acquisition section, a detection section, a determination section, a storage section, and a calculation section. The acquisition unit acquires a panoramic X-ray image of a child's tooth germ. The detection unit detects the type of tooth germ from the panoramic X-ray image using a first learning model obtained by causing a first artificial intelligence to learn in advance the relationship between the ROI (Region of Interest) and the type of tooth germ. To identify and detect tooth germs. The determining unit determines the developmental stage of each tooth germ detected by the detecting unit using a second learning model obtained by causing a second artificial intelligence to learn in advance the relationship between the shape of the tooth germ and the developmental stage. judge. The storage unit stores in advance reference values for each developmental stage of the tooth germ. The calculating section calculates the tooth age of each tooth germ detected by the detecting section using the determination result of the determining section and the reference value, and calculates the tooth age of each tooth germ detected by the detecting section from the tooth age of each tooth germ detected by the detecting section. Calculate a child's dental age.

According to the present invention, tooth age is automatically calculated. This makes it possible for dentists to save time and effort in manually calculating tooth age, increasing the possibility that they can focus on their primary medical practice. Furthermore, since dental age becomes information that can be easily used even by dentists who are not familiar with dental age, the present invention provides patients with the benefit of improving the quality of pediatric dental care nationwide. It is thought that this will contribute to disseminating knowledge about dental age among dentists.

Diagram showing an example of the configuration of a computer Functional block diagram showing an example of computer functions Flowchart showing the general operation of the dental age calculation device A diagram showing an example of a panoramic X-ray image including information indicating the relationship between an ROI manually set at the position of a tooth germ and the type of tooth germ corresponding to the ROI. Diagram showing examples of learning X-ray images of tooth germs Diagram showing the relationship between tooth germ shape and developmental stage A diagram showing an example of reference values stored in advance in the storage unit

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of the configuration of a computer. The computer 1 includes a control section 11 , a communication section 12 , a VRAM (Video Random Access Memory) 13 , a display section 14 , a storage section 15 , and an operation section 16 .

The control unit 11 controls the entire computer 1. The control unit 11 includes, for example, a CPU (Central Processing Unit) that performs arithmetic processing, a RAM (Random Access Memory) that provides a working memory, and a ROM (Read Only Memory) that records fixed programs and data.

The communication unit 12 communicates with the outside. The communication method between the communication unit 12 and the outside may be wired communication, wireless communication, or a combination of wired and wireless communication. Examples of the external device include a dental X-ray imaging device that takes panoramic X-ray images, a storage device that stores panoramic X-ray images taken by the dental X-ray imaging device, and the like.

VRAM 13 temporarily stores image data. The display unit 14 displays images based on the image data stored in the VRAM 13. As the display unit 14, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, etc. can be used.

The storage unit 15 stores a tooth age calculation program, image data, reference values for each developmental stage of tooth germ, various learning models, and the like. As the storage unit 15, for example, a flash memory, a hard disk drive, etc. can be used.

The operation unit 16 transmits a signal to the control unit 11 according to the user's operation. As the operation unit 16, a keyboard, a pointing device, etc. can be used.

FIG. 2 is a functional block diagram showing an example of the functions of the computer 1. The computer 1 functions as a tooth age calculation device 2 by executing a tooth age calculation program. The tooth age calculation device 2 includes an acquisition section 21, a detection section 22, a determination section 23, a storage section 24, and a calculation section 25. The tooth age calculation device 2 inputs data D1 of a panoramic X-ray image of a child's tooth germ, and outputs data D2 of the tooth age of each tooth germ and the tooth age of the child.

Here, with reference to FIG. 2 mentioned above, the general operation of the dental age calculation device 2 will be explained according to the flowchart of FIG. 3.

First, the acquisition unit 21 acquires data D1 of a panoramic X-ray image of a child's tooth germ (step S1).

Next, the detection unit 22 uses the first learning model to identify the type of tooth germ from the panoramic X-ray image acquired by the acquisition unit 21 and detects the tooth germ (step S2). The first learning model is obtained by making the first artificial intelligence learn the relationship between the ROI and the type of tooth germ in advance.

The first artificial intelligence uses, for example, the panoramic X-ray image shown in FIG. 4 as training data to learn in advance the relationship between the ROI and the type of tooth germ. In order to generate a first learning model with high detection accuracy, it is desirable to secure a large number of samples of panoramic X-ray images to be used as training data.

The panoramic X-ray image shown in FIG. 4 includes information indicating the relationship between an ROI manually set at the position of a tooth germ and the type of tooth germ corresponding to the ROI.

The rectangular ROI labeled "U1" corresponds to the tooth germ of the maxillary central incisor. The ROI on the right labeled "U1" is the image region containing the entire tooth germ of the right maxillary central incisor. The left ROI labeled “U1” is the image region containing the entire tooth germ of the left maxillary central incisor.

The rectangular ROI labeled "U2" corresponds to the tooth germ of the maxillary lateral incisor. The ROI on the right labeled "U2" is the image region containing the entire tooth germ of the right maxillary lateral incisor. The left ROI labeled "U2" is the image region containing the entire tooth germ of the left maxillary lateral incisor.

The rectangular ROI labeled "U3" corresponds to the tooth germ of the maxillary canine tooth. The ROI on the right labeled "U3" is the image region containing the entire tooth germ of the right maxillary canine. The ROI on the left labeled "U3" is the image region containing the entire tooth germ of the left maxillary canine.

The rectangular ROI labeled "U4" corresponds to the tooth germ of the maxillary first premolar. The ROI on the right labeled "U4" is the image region containing the entire tooth germ of the right maxillary first premolar. The ROI on the left labeled "U4" is the image region containing the entire tooth germ of the left maxillary first premolar.

The rectangular ROI labeled "U5" corresponds to the tooth germ of the maxillary second premolar. The ROI on the right labeled "U5" is the image region containing the entire tooth germ of the upper second premolar on the right. The ROI on the left labeled "U5" is the image region containing the entire tooth germ of the left maxillary second premolar.

The rectangular ROI labeled "U6" corresponds to the tooth germ of the maxillary first molar. The ROI on the right labeled "U6" is the image region containing the entire tooth germ of the upper first molar on the right. The ROI on the left labeled "U6" is the image region containing the entire tooth germ of the left maxillary first molar.

The rectangular ROI labeled "U7" corresponds to the tooth germ of the maxillary second molar. The ROI on the right labeled "U7" is the image region containing the entire tooth germ of the upper second molar on the right. The ROI on the left labeled "U7" is the image region containing the entire tooth germ of the left maxillary second molar.

The rectangular ROI labeled “L1” corresponds to the tooth germ of the mandibular central incisor. The ROI on the right labeled “L1” is the image region containing the entire tooth germ of the right mandibular central incisor. The left ROI labeled “L1” is the image region containing the entire tooth germ of the left mandibular central incisor.

The rectangular ROI labeled "L2" corresponds to the tooth germ of the mandibular lateral incisor. The right ROI labeled "L2" is the image region containing the entire tooth germ of the right mandibular lateral incisor. The left ROI labeled "L2" is the image region containing the entire tooth germ of the left mandibular lateral incisor.

The rectangular ROI labeled “L3” corresponds to the tooth germ of the mandibular canine. The ROI on the right labeled "L3" is the image region containing the entire tooth germ of the right mandibular canine. The left ROI labeled “L3” is the image region containing the entire tooth germ of the left mandibular canine.

The rectangular ROI labeled "L4" corresponds to the tooth germ of the mandibular first premolar. The right ROI labeled "L4" is the image region containing the entire tooth germ of the right mandibular first premolar. The ROI on the left labeled "L4" is the image region containing the entire tooth germ of the mandibular first premolar on the left.

The rectangular ROI labeled "L5" corresponds to the tooth germ of the mandibular second premolar. The ROI on the right labeled "L5" is the image region containing the entire tooth germ of the mandibular second premolar on the right. The ROI on the left labeled "L5" is the image region containing the entire tooth germ of the mandibular second premolar on the left.

The rectangular ROI labeled "L6" corresponds to the tooth germ of the mandibular first molar. The ROI on the right labeled "L6" is the image region containing the entire tooth germ of the right mandibular first molar. The left ROI labeled "L6" is the image region containing the entire tooth germ of the left mandibular first molar.

The rectangular ROI labeled "L7" corresponds to the tooth germ of the mandibular second molar. The right ROI labeled "L7" is the image region containing the entire tooth germ of the right mandibular second molar. The ROI on the left labeled "L7" is the image region containing the entire tooth germ of the mandibular second molar on the left.

In step S3 following step S2, the determination unit 23 determines the developmental stage of each tooth germ detected by the detection unit 22 using the second learning model. The second learning model is obtained by making the second artificial intelligence learn in advance the relationship between the shape of the tooth germ and the developmental stage.

For example, the second artificial intelligence uses, as training data, data in which the developmental stage is manually labeled for a learning X-ray image of a tooth germ, in which the type of tooth germ is given as meta information. Learn the relationship between shape and developmental stage in advance. In order to generate a second learning model with high determination accuracy, it is desirable to secure a large number of samples of learning X-ray images of tooth germs used as constituent elements of the teacher data. The three X-ray images shown in FIG. 5 are examples of learning X-ray images of tooth germs.

In this embodiment, the labeling of development stages is eight stages. That is, the determining unit 23 evaluates the developmental stages by dividing the developmental stages into stages 1 to 8.

As shown in FIG. 6, the first stage includes a tooth germ formation period, a calcification initiation period, a crown formation period initiation period, and a 1/2 period of the tooth crown formation period. The second stage includes the 3/4 stage of the crown formation stage, as shown in FIG. The third stage includes the completion stage of the tooth crown formation stage, as shown in FIG. The fourth stage includes the quarter stage of the tooth root formation stage, as shown in FIG. The fifth stage includes the 1/2 stage of the tooth root formation stage, as shown in FIG. The sixth stage includes the 3/4 stage of the tooth root formation stage, as shown in FIG. The seventh stage includes the completion stage of the tooth root formation stage, as shown in FIG. The eighth stage includes the apical closure stage as shown in FIG. The tooth germ formation period, the calcification initiation period, and the initiation period of the tooth crown formation period are defined only for second premolars, second molars, and third molars. Furthermore, when a plurality of children were investigated, the number of tooth germs that were determined to be in the tooth germ formation stage, the calcification stage, or the beginning of the crown formation stage was also small. Therefore, there is little significance in classifying the tooth germ formation period, the calcification initiation period, and the tooth crown formation period as independent developmental stages. Therefore, in this embodiment, as described above, the tooth germ formation period, the calcification initiation period, and the initiation period of the tooth crown formation period are combined with the 1/2 period of the tooth crown formation period as the first stage. This makes it possible to standardize the developmental stage evaluation process for all types of tooth germs. Note that "front teeth" in FIG. 6 include "central incisors", "lateral incisors", and "canine teeth". Furthermore, in the present embodiment, as shown in FIG. 6, the determination unit 23 classifies tooth germs into two types: front teeth or premolars and molars, and evaluates the developmental stage. This minimal classification simplifies the process of evaluating developmental stages. However, the classification of tooth germs is not limited to two. For example, the determination unit 23 may classify the tooth germ into three categories, namely, front teeth, premolars, and molars, and evaluate the developmental stage. For example, the determination unit 23 may classify the tooth germ into four types: incisors, canines, premolars, and molars, and evaluate the developmental stage. For example, the determination unit 23 may classify tooth germs by tooth germ type (for example, the 14 types of labels shown in FIG. 4) and evaluate the developmental stage.

As described above, in this embodiment, the growth stages are divided into eight stages, but the number of divisions in the growth stages is not limited to eight stages.

For example, the five stages shown in FIG. 6 may be a tooth germ formation stage, a calcification initiation stage, a tooth crown formation stage, a tooth root formation stage, and an apical closure stage.

For example, the tooth germ formation stage, the calcification initiation stage, the beginning of the crown formation stage, the 1/2 stage of the crown formation stage, the 3/4 stage of the crown formation stage, and the completion of the crown formation stage are shown in Fig. 6. There may be 11 stages: 1/4 stage of tooth root formation stage, 1/2 stage of tooth root formation stage, 3/4 stage of tooth root formation stage, completed stage of tooth root formation stage, and apical closure stage.

For example, the 11 periods shown in FIG. 6 may be arbitrarily combined to form 6 to 10 stages. Further, it may be simplified to 4 stages or less, or it may be detailed to 12 stages or more.

In step S4 following step S3, the calculation unit 25 calculates the child's dental age. More specifically, the calculation unit 25 calculates the tooth age of each tooth germ detected by the detection unit 22 using the determination result of the determination unit 23 and the reference value stored in advance in the storage unit 24. Then, the calculation unit 25 calculates the child's tooth age from the tooth age of each tooth germ detected by the detection unit 22.

FIG. 7 is a diagram showing an example of reference values stored in advance in the storage unit 24. The storage unit 24 stores the reference value in the form of a data table. The reference value means the tooth age according to the developmental stage of the tooth germ. Note that in this embodiment, reference values are set for boys and girls respectively, but reference values may be set regardless of boys and girls. In this embodiment, reference values are set for each boy and girl, so for example, information indicating whether the child is a boy or a girl is included in the meta information of the panoramic X-ray image acquired by the acquisition unit 21. Good.

A specific method for calculating the child's tooth age from the tooth age of each tooth germ detected by the detection unit 22 is to use the simple average of the tooth age of each tooth germ detected by the detection unit 22 as the child's tooth age. Alternatively, the weighted average of the tooth ages of the respective tooth germs detected by the detection unit 22 may be used as the child's tooth age. In the case of a weighted average, for example, a large weight may be given to tooth types whose tooth germ shape is easy to clearly grasp, and a small weight may be given to tooth types whose tooth germ shape is difficult to clearly grasp.

When the process of step S4 is completed, the operation of the flowchart shown in the figure is completed. The tooth age of each tooth germ determined by the calculation unit 25 in step S4 and the data D2 of the child's tooth age calculated by the calculation unit 25 in step S4 are output from the tooth age calculation device 2.

That is, the dental age calculation device 2 automatically calculates the child's dental age. This makes it possible for dentists to save time and effort in manually calculating tooth age, increasing the possibility that they can focus on their primary medical practice. Furthermore, since dental age becomes information that can be easily used even by dentists who are not familiar with dental age, the present invention provides patients with the benefit of improving the quality of pediatric dental care nationwide. It is thought that this will contribute to disseminating knowledge about dental age among dentists.

The above embodiments should be considered to be illustrative in all respects and not restrictive, and the technical scope of the present invention is indicated by the claims rather than the description of the above embodiments. It should be understood that all changes that come within the meaning and range of equivalence of the claims are included.

For example, in the above embodiment, the tooth age calculation device 2 outputs the data D2 of the tooth age of each tooth germ and the child's tooth age, but the tooth age calculation device 2 does not output data of the tooth age of each tooth germ. Data on the child's dental age may also be output.

1 Computer 11 Control unit 12 Communication unit 13 VRAM
14 Display section 15 Storage section 16 Operation section 2 Dental age calculation device 21 Acquisition section 22 Detection section 23 Judgment section 24 Storage section 25 Calculation section

Claims (4)

an acquisition unit that acquires a panoramic X-ray image of a child's tooth germ;
Multiple types of tooth germs are determined from the panoramic X-ray image using a first learning model obtained by having a first artificial intelligence learn in advance the relationship between ROI (Region of Interest) and each of multiple types of tooth germs. a detection unit that identifies each tooth germ and detects the tooth germ;
a determination unit that determines the developmental stage of each tooth germ detected by the detection unit using a second learning model obtained by making a second artificial intelligence learn in advance the relationship between the shape of the tooth germ and the developmental stage; ,
a memory unit that stores in advance reference values for each developmental stage of the tooth germ;
The tooth age of each tooth germ detected by the detection unit is determined using the determination result of the determination unit and the reference value, and the tooth age of the child is determined from the tooth age of each tooth germ detected by the detection unit. A calculation department that calculates;
A dental age calculation device equipped with: The determination unit determines the developmental stage,
A first stage including a tooth germ formation period, a calcification initiation period, a crown formation period initiation period, and a 1/2 period of the tooth crown formation period;
a second stage comprising 3/4 stage of the crown formation stage;
a third stage including a completion stage of the crown formation stage;
The 4th stage, which includes 1/4 stage of the tooth root formation stage,
a fifth stage including 1/2 stage of the tooth root formation stage;
a sixth stage including 3/4 stage of the tooth root formation stage;
The tooth age estimating device according to claim 1, wherein the developmental stage is evaluated by dividing into a seventh stage including the completion stage of the tooth root formation stage and an eighth stage including the apical closure stage. The tooth age calculation device according to claim 1 or 2, wherein the determination unit evaluates the developmental stage by classifying the tooth germ into two types: front teeth or premolars and molars. computer,
an acquisition unit that acquires a panoramic X-ray image of a child's tooth germ;
Multiple types of tooth germs are determined from the panoramic X-ray image using a first learning model obtained by having a first artificial intelligence learn in advance the relationship between ROI (Region of Interest) and each of multiple types of tooth germs. a detection unit that identifies each tooth germ and detects it;
a determination unit that determines the developmental stage of each tooth germ detected by the detection unit using a second learning model obtained by causing a second artificial intelligence to learn in advance the relationship between the shape of the tooth germ and the developmental stage; and Determining the tooth age of each tooth germ detected by the detection unit using the determination result of the determination unit and reference values for each developmental stage of the tooth germ stored in advance in the storage unit of the computer, and determining the tooth age of each tooth germ detected by the detection unit, a calculation unit that calculates the tooth age of the child from the tooth age of each tooth germ detected by the unit;
A dental age calculation program to function as a dental age calculation program.

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