JP7757045B2 - Dental prosthesis color estimation method, information processing device, and dental prosthesis manufacturing method - Google Patents

Description

The present invention relates to a method for estimating the color of a dental prosthesis, an information processing device, and a method for manufacturing a dental prosthesis that uses estimated color data to color the dental prosthesis.

Traditionally, dental prostheses such as inlays, crowns, and bridges have been produced manually, such as by dental technicians using casting. In contrast, CAD/CAM systems, which use computers to design dental prostheses such as inlays, crowns, and bridges and then produce them through cutting processes, are attracting attention (Patent Document 1).

The CAD/CAM system described in Patent Document 1 reads information about the three-dimensional shape of a tooth for which an abutment tooth or cavity has been formed, and in some cases, information about the three-dimensional shape of adjacent teeth and opposing teeth. The system then uses the read information about the tooth shape to design the desired dental prosthesis on a computer, and then places a block of material such as hardened resin, sintered ceramic, or metal in an automatic cutting machine and cuts it to create the dental prosthesis.

Japanese Patent Application Laid-Open No. 2002-224142

Patent Document 1 describes a method for forming a dental prosthesis by cutting a block of material based on information about the three-dimensional shape of teeth and other objects using a CAD/CAM system, but coloring the dental prosthesis is done manually, which is costly. The present invention aims to provide a color estimation method for estimating the color of a dental prosthesis, an information processing device that implements the estimation method, and a method for manufacturing a dental prosthesis that colors the dental prosthesis based on the estimated color.

In order to achieve the object of the present invention, a method for estimating the color of a dental prosthesis according to the present invention includes:
an acquisition step of acquiring tooth color information obtained using an imaging means;
Among a target tooth on which a dental prosthesis is to be placed, a tooth adjacent to the target tooth, and a corresponding tooth to the target tooth,
an estimation step in which a computing unit estimates the color of the surface of the dental prosthesis based on at least one piece of color information ;
In the estimation process, the missing part of the tooth is identified, the tooth having the identified missing part is determined as the target tooth on which the dental prosthesis will be placed, the degree of loss of the missing part of the tooth is estimated, and the color of the dental prosthesis is estimated according to the degree of loss.

The present invention makes it possible to estimate the color of a formed dental prosthesis.

1 is a diagram showing the configuration of a dental prosthesis manufacturing system according to the present invention. FIG. 2 is a diagram showing a flow of producing a dental prosthesis according to the present invention. 1 is an image diagram of a production flow of a dental prosthesis according to the present invention. 1 is a schematic diagram of an example of an apparatus for realizing each part of the dental prosthesis manufacturing system of the present invention. 1 is a schematic diagram of an intraoral scanner 1000 of the present invention. 1 is a schematic diagram of a dental CAD 2000 of the present invention. FIG. 2 is a flow chart showing data generation for a dental prosthesis using the dental CAD of the present invention. Schematic diagram of a dental CAM 3000 of the present invention. 1A to 1C are diagrams illustrating a flow of forming a dental prosthesis according to the present invention. 4 is a schematic diagram of a coloring device 4000 of the present invention. 3A to 3C are diagrams illustrating a coloring flow of the dental prosthesis of the present invention.

A preferred embodiment of the present invention will now be described with reference to the accompanying drawings.

[First embodiment]
FIG. 1 shows the configuration of a dental prosthesis manufacturing system according to the present invention.

The dental prosthesis manufacturing system of the present invention includes an intraoral information acquisition unit 100 that acquires intraoral information, and a data generation unit 200 that generates three-dimensional shape data and color data for the dental prosthesis based on the acquired intraoral information. The dental prosthesis manufacturing system further includes a formation unit 300 that forms the dental prosthesis based on the generated three-dimensional shape data, and a coloring unit 400 that colors the surface of the formed dental prosthesis based on the generated color data. Here, the data generation unit 200 and the coloring unit 400 that colors based on the color data generated by the data generation unit 200 function as a dental prosthesis coloring system 500. That is, the coloring system includes the data generation unit 200 that generates tooth color data based on tooth color information, and the coloring unit 400 that colors the surface of the formed dental prosthesis based on the color data. The formation unit 300 and coloring unit 400 may be configured as the same device that performs both processes.

The following explains the flow for producing a dental prosthesis using the dental prosthesis manufacturing system shown in Figure 2, with reference to the image diagram in Figure 3.

In step S200, the intraoral information acquisition unit 100 acquires intraoral information of the subject from a storage device or the like. The information acquired by the intraoral information acquisition unit 100 includes information on the three-dimensional shape of the teeth and tooth color information. The intraoral information acquisition unit 100 transmits the acquired intraoral information to the data generation unit 200. Note that the intraoral information acquired by the intraoral information acquisition unit 100 here may be intraoral information captured using imaging means such as an intraoral scanner (see 301 in Figure 3) and transmitted from the imaging device. 301 in Figure 3 shows an image of acquiring intraoral information of a user. The intraoral information acquisition unit 100 acquires intraoral information of the subject captured using imaging means.

In step S201, the data generation unit 200 uses a calculator to estimate the surface color of the dental prosthesis based on the intraoral information. The data generation unit 200 further estimates the three-dimensional shape of the dental prosthesis from the intraoral information, and generates three-dimensional tooth shape data and tooth color data based on the estimated color and shape (see 302 in Figure 3). The data generation unit 200 may estimate the three-dimensional shape of the dental prosthesis and generate three-dimensional tooth shape data, for example, based on the difference between master tooth shape information and the transmitted three-dimensional tooth shape information. After generating the three-dimensional tooth shape data and tooth color data, the data generation unit 200 transmits the generated three-dimensional shape data to the formation unit 300 and transmits the color data to the coloring unit 400.

In 302 of Figure 3, the dental prosthesis is shown in a dark color, and the existing teeth are shown in a light color. As will be described later, the data generation unit 200 estimates the color that will be applied to the surface of the dental prosthesis and generates data on the dental prosthesis based on the estimated color.

The data generation unit 200 generates three-dimensional tooth shape data and tooth color data based on the intraoral information acquired by the intraoral information acquisition unit 100. The three-dimensional tooth shape data and color data generated by the data generation unit 200 may be mutually related data. As will be described in detail later, for example, the color of the surface of a dental prosthesis is estimated by a calculator based on color information for at least one of the target tooth of the dental prosthesis, teeth adjacent to the target tooth, and teeth corresponding to the target tooth. Color estimation may also be performed based on three-dimensional tooth shape information. In such cases, the color data generated by the data generation unit 200 is based on the three-dimensional tooth shape information and color information, and therefore the generated three-dimensional shape data and color data have a correlation between the two pieces of data.

In step S202, the forming unit 300 forms a dental prosthesis by cutting and grinding the base material of the dental prosthesis based on the acquired three-dimensional shape data of the tooth. Once the dental prosthesis has been formed by the forming unit 300, the formed dental prosthesis is sent to the coloring unit 400.

In step S203, the coloring unit 400 colors the surface of the dental prosthesis obtained from the forming unit 300 based on the acquired dental prosthesis color data. 303 in Figure 3 shows an image of the dental prosthesis being formed from the dental prosthesis base material by the forming unit 300, and the coloring unit 400 coloring the formed dental prosthesis.

This flow allows the dental prosthesis coloring system 500 of the present invention to color the formed dental prosthesis. Coloring the dental prosthesis using the coloring system 500 can produce a highly compatible dental prosthesis, as shown in the image at 304 in Figure 3.

Here, an example of a device that realizes each part of the dental prosthesis manufacturing system will be described using Figure 4. The function of the intraoral information acquisition unit 100 is realized, for example, by an intraoral scanner 1000 (described later using Figure 5). The intraoral information captured by the intraoral scanner 1000 is transmitted to a dental CAD 2000 (described later using Figure 6) that has the function of a data generation unit 200. The three-dimensional shape data of the dental prosthesis generated by the dental CAD 2000 is transmitted to a dental CAM 3000 (described later using Figure 7) that has the function of a formation unit 300. The color data generated by the dental CAD 2000 is transmitted to a coloring device 4000 (described later using Figure 9) that has the function of a coloring unit 400. The dental CAD 2000 and the coloring device 4000 may also function as a dental prosthesis coloring system 5000 that is an integrated unit. Note that the devices that realize each part of the dental prosthesis manufacturing system are not limited to those described above. Below, we will explain each device that makes up the dental prosthesis manufacturing system described above.

<Intraoral Scanner 1000>
First, a schematic diagram of the intraoral scanner 1000 that realizes the functions of the intraoral information acquisition unit 100 in the dental prosthesis manufacturing system will be described using FIG. 5 . The intraoral scanner 1000 includes a memory unit 501, an operation unit 502, a communication IF (Interface) 503, and an imaging control unit 504. The memory unit 501 stores acquired tooth information, etc., and the operation unit 502 accepts user operations. The communication IF 503 is implemented by a LAN card or the like and controls communication with an external device (e.g., a dental CAD 2000). The imaging control unit 504 acquires three-dimensional tooth shape information and tooth color information. Here, the three-dimensional tooth shape information and color information acquired by the imaging control unit 504 may be acquired simultaneously or separately. Furthermore, the three-dimensional tooth shape information and color information acquired by the imaging control unit 504 may each be configured by independent devices.

The three-dimensional shape information and color information of the teeth acquired by the imaging control unit 504 are stored in the memory unit 501 and transmitted to the dental CAD 2000 using the communication IF 503. The intraoral information acquisition unit 100 may be realized by a device that acquires pre-imaged intraoral information from a storage device, etc. The intraoral scanner 1000 is a scanner for acquiring intraoral information, and does not necessarily need to be inserted into the oral cavity to capture images. For example, the intraoral information acquisition unit 100 may take a seal inside the oral cavity and scan it to acquire three-dimensional shape information of the teeth.

<Dental CAD 2000>
Next, an example of a schematic diagram of a dental CAD 2000, which is an information processing device that realizes the functions of the data generation unit 200 in the dental prosthesis manufacturing system, is shown. As shown in Figure 6, the dental CAD 2000 is an information processing device that includes a communication IF 601, a ROM 602, a RAM 603, a storage unit 604, an operation unit 605, a display unit 606, and a control unit 607.

The communication IF 601 is realized by a LAN card or the like, and is responsible for communication with the external intraoral scanner 1000, dental CAM 3000, and coloring device 4000. However, if communication is not required, the communication IF 601 is not a required component. The ROM 602 is realized by non-volatile memory or the like, and stores various programs, etc. The RAM 603 is realized by volatile memory or the like, and temporarily stores various information. The storage unit 604 is realized by an HDD (Hard Disk Drive) or SSD (Solid State Drive), etc., and stores various information. The operation unit 605 is realized by a keyboard, mouse, etc., and the display unit 606 is realized by a display or the like, and displays various information to the user. The operation unit 605 and display unit 606 may function as components of dental CAD 2000 as shown in this drawing, or may be configured as devices separate from dental CAD 2000.

The control unit 607 includes an acquisition unit 608 that acquires tooth color information obtained using an imaging means, and a calculator that estimates the surface color of the dental prosthesis based on color information for at least one of the target tooth on which the dental prosthesis will be placed, the teeth adjacent to the target tooth, and the corresponding teeth of the target tooth. The data generation unit 610 also includes a data generation unit 610 that generates data for the dental prosthesis based on the estimated color and three-dimensional shape of the dental prosthesis, and a display control unit 611 that displays the generated data on the display unit 606.

Here, using Figure 7, we will explain the flow of data generation for dental prostheses using dental CAD 2000. Note that each component of dental CAD 2000 may be configured as multiple devices, or as a device that realizes only some of the components.

In step S710, the acquisition unit 608 acquires tooth color information obtained using the imaging means. Once the acquisition unit 608 acquires the tooth color information, it transmits the tooth color information to the estimation unit 609, and this step ends.

In step S711, the estimation unit 609 estimates the surface color of the dental prosthesis based on color information for at least one of the target tooth on which the dental prosthesis will be placed, the teeth adjacent to the target tooth, and the corresponding teeth of the target tooth. The estimation unit 609 transmits the estimated surface color information of the dental prosthesis to the data generation unit 610, and then ends this step. The target tooth refers to a tooth with a missing portion, and the adjacent tooth refers to an adjacent tooth in the dentition on the same jaw side of the maxilla or mandible where the target tooth is located. The corresponding tooth refers to a tooth located in an occlusal position with the target tooth in the dentition on a different jaw side from the maxilla or mandible where the target tooth is located.

Here, the target tooth, nearby teeth, and corresponding teeth that serve as input for estimation in the estimation unit 609 may be identified by the user or may be identified using known image processing techniques.

The estimation unit 609 estimates the surface color of the dental prosthesis using brightness data generated based on brightness information of at least one of the target tooth on which the dental prosthesis will be placed, a tooth near the position where the dental prosthesis will be placed, or a tooth corresponding to the tooth on which the dental prosthesis will be placed. In this case, the estimation unit 609 estimates the surface color of the dental prosthesis between the maximum and minimum values of the generated brightness data.

The estimation unit 609 may also perform processing to determine a missing tooth as the target tooth using image processing technology. Furthermore, the degree of loss of the missing portion of the target tooth is calculated, and the estimation unit 609 estimates the color of the surface of the dental prosthesis according to the degree of loss. For example, when the degree of loss is large, the estimation unit 609 weights the color information of the corresponding tooth and neighboring teeth more heavily than the color information of the target tooth in the estimation than when the degree of loss is small. On the other hand, when the degree of loss is small, the estimation unit 609 weights the color information of the target tooth more heavily than the color information of the corresponding tooth and neighboring teeth in the estimation than when the degree of loss is large. The tooth color of the surface of the dental prosthesis in the estimation unit 609 is estimated by interpolating the color of the missing portion from the color information of the target tooth, corresponding tooth, and neighboring teeth. For example, the average color value of the color information of multiple teeth may be estimated as the color of the dental prosthesis.

The estimation unit 609 stores a tooth color model that associates tooth color with three-dimensional shape information, and one example is to estimate the color of a dental prosthesis by inputting color information into the color model.

The surface color of the dental prosthesis estimated by the estimation unit 609 may include a color with a lower hue b* than the hue b* in the chromaticity coordinates defined by the CIE 1976 L*a*b* color system. Furthermore, of the colors estimated by the estimation unit 609, a color with a lower hue b* is applied to part of the surface of the dental prosthesis. It is more desirable to apply this color to the tooth tips and their surrounding areas, which are part of the dental prosthesis, as this provides excellent aesthetic appeal.

In step S712, the data generation unit 610 generates color data for the dental prosthesis based on the transmitted color information for the dental prosthesis and displays the generated color data on the display unit 606 via the display control unit 611. The generated color data is also transmitted to the coloring device 4000, which, as described below, colors the formed dental prosthesis based on the estimated color information.

The estimation unit 609 may estimate a plurality of candidate colors for the surface of the dental prosthesis. In this case, the display control unit 611 displays a plurality of candidate color colors for the surface of the dental prosthesis on the display unit 606. The user may select color data from the plurality of candidate colors via the operation unit 605 or the like. The plurality of candidate color data displayed on the display unit 606 may also be displayed together with at least one matching score for the tooth on which the dental prosthesis will be placed, a tooth near the position where the dental prosthesis will be placed, or color information for the tooth corresponding to the tooth on which the dental prosthesis will be placed.

(Variation 1)
The acquisition unit 608 may further acquire information on the three-dimensional shape of the teeth. In this case, the estimation unit 609 is configured to estimate the surface color of the dental prosthesis based on two pieces of information: tooth color information and three-dimensional shape information, which is expected to improve estimation accuracy. Furthermore, the information generated by the data generation unit 610 may be three-dimensional shape data of the dental prosthesis in addition to color data of the dental prosthesis, and the dental CAM 3000 (described later) may form the dental prosthesis based on the three-dimensional shape data. Furthermore, when the estimation unit 609 acquires the three-dimensional shape information, it may generate predicted data on the appearance of the dental prosthesis from outside the oral cavity of the subject based on the position or posture at which the dental prosthesis will be placed, and estimate the surface color of the dental prosthesis based on the predicted data. Furthermore, the estimation unit 609 may estimate the surface color of the dental prosthesis based on at least one of light source position information, the intensity of light emitted by the light source, the frequency of the light, or the color of the light.

<Dental CAM3000>
An example of the configuration of the dental CAM 3000 will be described with reference to FIG. 8, and the process of forming a dental prosthesis will be described with reference to FIG.

The dental CAM 3000 comprises a communication IF 701, a processing unit 702, a memory unit 703, an operation unit 704, a display unit 705, and a control unit 706. The control unit 706 comprises a processing control unit 707 and a display control unit 708.

In step S801, dental CAM 3000 receives the three-dimensional shape data generated by dental CAD 2000 via communication IF 801. The received three-dimensional shape data is stored in memory unit 803. Dental CAM 3000 may also acquire tooth color data. The tooth color data will be used in steps described below.

In step S802, the dental CAM 3000 selects a desired base material for the prosthesis based on the received three-dimensional shape data and color data. The selection of the base material for the prosthesis may be replaced by a base material selection made by the user. This step may be omitted as appropriate, for example, if the base material for the prosthesis has been set in advance. Here, the prosthesis components selected by the dental CAM 3000 are preferably base materials for the prosthesis that are close to the tooth color data received by the dental CAM 3000 from the dental CAD 2000. For example, the base material for the dental prosthesis selected is a base material for the prosthesis that is close to the color data and has a high degree of whiteness. The base material for the dental prosthesis may also contain ceramics and/or resin.

In step S803, the dental CAM 3000 controls the processing unit 802 using the processing control unit 807, which is a component of the control unit 806, based on the received three-dimensional shape data, to process the base material of the dental prosthesis to form the dental prosthesis. The results of processing and forming by the processing unit 802 can be displayed on the display unit 805 via the display control unit 808. Here, the processing unit 802 may form the dental prosthesis by cutting and/or grinding the base material of the prosthesis. The processing unit 802 may also process and form the dental prosthesis by repeatedly irradiating the base material of the prosthesis with light to sequentially sinter or melt and solidify the raw materials. The processing unit 802 may form the dental prosthesis using an additive manufacturing method. The control unit 806 may also be controlled via the operation unit 804. The dental prosthesis formed by the dental CAM 3000 is used in the coloring process using the coloring device 4000.

<Coloring device 4000>
An example of a coloring device 4000 that realizes the function of the coloring unit 400 in the dental prosthesis manufacturing system will be described with reference to FIG. 10, and a dental prosthesis coloring process including this device will be described with reference to FIG.

The coloring device 4000 includes a communication IF 901, an operation unit 902, a memory unit 903, a rotation unit 904, a discharge unit 905, and a control unit 906. The control unit 906 includes a position detection unit 907, a shape detection unit 908, a rotation control unit 909, and a discharge control unit 910.

Below, using Figure 11, we will explain a specific example of the process of coloring a formed dental prosthesis based on the color data generated by the data generation unit 200.

In step S1001, the coloring device 4000 receives color data for the dental prosthesis generated by the dental CAD 2000 via the communication IF 901.

The coloring device 4000 records the received color data in the memory unit 903. The coloring device 4000 holds the dental prosthesis processed and formed by the dental CAM 3000 in the rotation unit 904. The position detection unit 907 detects position data of the dental prosthesis processed and formed by the dental CAM 3000. The shape detection unit 908 detects the shape of the dental prosthesis by receiving the position data of the dental prosthesis detected by the position detection unit 907 or three-dimensional shape data from the dental CAD 2000. Combining the position data detected by the position detection unit 907 with the received three-dimensional shape data improves the accuracy of detection of the shape of the dental prosthesis by the shape detection unit 908. Detection of the shape of the dental prosthesis by the shape detection unit 908 may be replaced by receiving three-dimensional shape data.

In step S1002, the coloring device 4000 colors the surface of the dental prosthesis formed by the forming device 3000 based on the color data generated by the dental CAD 2000. Specifically, the coloring device 4000 controls the rotation unit 904 with the rotation control unit 909 in accordance with the shape of the dental prosthesis detected by the shape detection unit 908, and colors the dental prosthesis processed and formed by the dental CAD 3000 with color material based on the color data while controlling the discharge unit 905 with the discharge control unit 910. Once the dental prosthesis has been colored, processing proceeds to step S1003. The discharge method of the discharge unit 905 may be inkjet or spray. Here, inkjet may be used for the discharge unit 905 when the amount of color material is small. Alternatively, spray may be used as the discharge unit 905 when the amount of color material is large. The discharge unit 905 may also have a mechanism that can switch between inkjet and spray. The coloring device 4000 may use two or more coloring materials to color the dental prosthesis, improving the reproducibility of the dental prosthesis' color data. The coloring device 4000 may also have an applicator (not shown) that applies coloring materials to the dental prosthesis. When the coloring device 4000 applies coloring materials, the applicator may perform multi-layer application using multiple different coloring materials. Multi-layer application by the applicator improves the reproducibility of the coloring of the dental prosthesis according to the color data. The multiple coloring materials may also have different refractive indices. Using coloring materials with different refractive indices to color the dental prosthesis increases reflectance, allowing for coloring reproducibility with a smaller application amount. The coloring material used to color the dental prosthesis by the coloring device 4000 may be selected by referencing a lookup table that links tooth color data with coloring materials. If the coloring device 4000 already has a lookup table, the computational cost associated with determining the coloring material can be reduced. The coloring material may include B, Si, or resin. A wide color space can be achieved by including B, Si, or resin in the coloring materials used to color dental prostheses.

Furthermore, the coloring material used to color the dental prosthesis by the coloring device 4000 may contain a scattering material. By using a coloring material containing a scattering material, color reproducibility can be achieved with a smaller amount of application. A scattering material with a high refractive index may be used. The scattering material with a high refractive index may contain at least one of TiO ₂ , SiO ₂ , and ZrO ₂ .

In step S1003, the coloring device 4000 determines whether the coloring process is complete. If it is determined that the coloring process is complete, the process ends. If it is determined that the coloring process is not complete, the process proceeds to step S1002, where the coloring process is performed.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples.

Example 1
Using the three-dimensional tooth shape data, a Yb fiber laser was irradiated onto the raw material to perform three-dimensional modeling. Powder 1 in Table 1 was used as the raw material. A three-dimensional shape measuring machine was used to confirm that a prosthesis identical to the three-dimensional tooth shape data had been created. The modeled prosthesis was then colored with a coloring material using an inkjet printer.

Example 2
As in Example 1, a prosthesis was fabricated using Powder 2 as the raw material.

It was confirmed that the prostheses of Examples 1 and 2 can be used as dental prostheses.

(Variation 2)
The data generating unit 200 estimates the surface color, for example, using the camera output (Rw, Gw, Bw) for the white light source color as frequency information of the light emitted by the light source. The surface color of the tooth adjacent to the tooth to be repaired with the prosthesis, captured by the camera, is assumed to be (R, G, B). The surface color of the tooth to be repaired with the prosthesis is estimated based on (R', G', B') in Equation 1.

(Variation 3)
The present invention can also be realized by executing the following process: software (programs) that realize the functions of the above-described embodiments are supplied to a system or device via a network or various storage media, and the computer (or CPU, MPU, etc.) of the system or device reads and executes the programs.

608 Acquisition unit 609 Estimation unit

Claims (17)

an acquisition step of acquiring tooth color information obtained using an imaging means;
Among a target tooth on which a dental prosthesis is to be placed, a tooth adjacent to the target tooth, and a corresponding tooth to the target tooth,
an estimation step in which a computing unit estimates the color of the surface of the dental prosthesis based on at least one piece of color information ;
A method for estimating the color of a dental prosthesis, characterized in that in the estimation step, a missing portion of the tooth is identified, the tooth having the identified missing portion is determined as the target tooth for placement of the dental prosthesis, the degree of loss of the missing portion of the tooth is estimated, and the color of the dental prosthesis is estimated according to the degree of loss . In the acquiring step, three-dimensional shape information of the teeth is further acquired,
2. The method for estimating the color of a dental prosthesis according to claim 1, wherein in the estimating step, the color of the dental prosthesis is estimated based on the color information and the three-dimensional shape of the tooth. 2. The method for estimating the color of a dental prosthesis according to claim 1, characterized in that, in the estimation step , when the degree of loss is large, the color of the dental prosthesis is estimated by weighting the color information of the teeth near the target tooth or the corresponding teeth of the target tooth more heavily than when the degree of loss is small. 4. The method for estimating the color of a dental prosthesis according to claim 3, wherein in the estimation step, when the degree of the loss is small, the color of the dental prosthesis is estimated by weighting the color information of the target tooth more heavily than when the degree of the loss is large . A method for estimating the color of a dental prosthesis according to any one of claims 1 to 4 , wherein the tooth near the target tooth is an adjacent tooth in the tooth row on the same jaw side as the target tooth in the upper or lower jaw where the target tooth is located. A method for estimating the color of a dental prosthesis according to any one of claims 1 to 5 , wherein the corresponding tooth to the target tooth is a tooth located in an occlusal position with the target tooth in a tooth row on a different jaw side relative to the upper or lower jaw in which the target tooth is located. 5. The method for estimating the color of a dental prosthesis according to claim 3 , wherein the color of the dental prosthesis is estimated by interpolating the color of a missing portion from the tooth color information. The method for estimating the color of a dental prosthesis according to claim 7 , characterized in that the color of the missing part is estimated by inputting color information of the target tooth into a tooth color model that associates information on the color and shape of the tooth. 9. The method for estimating the color of a dental prosthesis according to claim 1, wherein in the estimation step, the color of the surface of the dental prosthesis is estimated using lightness data generated based on lightness information of at least one of the target tooth on which the dental prosthesis is to be placed, a tooth in the vicinity of the position where the dental prosthesis is to be placed, or a tooth corresponding to the tooth on which the dental prosthesis is to be placed . 10. The method for estimating the color of a dental prosthesis according to claim 9 , wherein the calculator estimates the color of the dental prosthesis so as to be between a maximum value and a minimum value in the lightness data. 11. A method for estimating the color of a dental prosthesis according to claim 1, further comprising estimating the color of the surface of the dental prosthesis based on predicted data of the appearance of the dental prosthesis from outside the oral cavity of the subject, the data being based on the position or posture at which the dental prosthesis is placed. 12. The method for estimating the color of a dental prosthesis according to claim 1, wherein a color having a lower hue b* than the hue b* in chromaticity coordinates defined in the CIE 1976 L*a*b* color system included in the tooth color data is estimated as the color of a portion of the surface of the dental prosthesis. The method for estimating the color of a dental prosthesis according to claim 12 , wherein the part is the tip of the dental prosthesis and a portion in the vicinity thereof. 6. The method for estimating the color of a dental prosthesis according to claim 1, wherein the color of the surface of the dental prosthesis is estimated based on at least one of information on the positioning of a light source, the intensity of light emitted by the light source, the frequency of the light, or the color of the light. 15. A method for estimating the color of a dental prosthesis according to claim 1, further comprising a step of selecting, as a color material for coloring the surface of the dental prosthesis, a color material associated by a lookup table that links the estimated surface color of the dental prosthesis with a color material for coloring the surface of the dental prosthesis. A method for manufacturing a dental prosthesis, comprising: a step of estimating the color of the surface of a dental prosthesis by the method for estimating the color of a dental prosthesis according to any one of claims 1 to 15 ; and a step of coloring the surface of the dental prosthesis using a coloring device based on the estimated color. An information processing device that estimates the color of the surface of a dental prosthesis by implementing the method for estimating the color of a dental prosthesis according to any one of claims 1 to 15 .