Color management method for customized dental restorations

Abstract

A computer-implemented method for creating a color 3D model for a dental restoration includes receiving tooth color information, a color distribution map, and a geometry. The color information is assigned to the color distribution map. The color information and color distribution map are then combined with the geometry to create a digital color 3D model. The resulting 3D model includes volumes of different color materials for the restoration to provide color transition zones, which can be 3D printed from the 3D model to manufacture a corresponding restoration.

Description

[Background technology]

[0001] One of the main reasons for reworking dental restorations is that the color and aesthetics do not match the patient's situation. The color matching and aesthetics of dental restorations also mean that aesthetic restorations tend to be more expensive than, for example, porcelain-fused-to-metal (PFM) or monolithic ones. Therefore, there is a need for digital workflows or software that can generate color-customized dental restorations for individual patients. Summary of the Invention

[0002] A computer-implemented method for creating a color 3D model for a dental restoration includes receiving tooth color information, a color distribution map, and a shape. The color information is assigned to the color distribution map. The color information and color distribution map are combined with the shape, and a color 3D model is created based on the assigned color information and color distribution map combined with the shape.

[0003] Another computer-implemented method for creating a color 3D model for a dental restoration includes extracting a color distribution map from a digital representation of a tooth and selecting a boundary of the color distribution map. The boundary of the color distribution map is combined with the digital representation and matched to a digital 3D model of the tooth. The outer surface of the digital 3D model is reduced to accommodate a segment of the color distribution map, and the outer surface of the digital 3D model is converted to a digital 3D volumetric model.

[0004] The result of these methods can be a 3D model with volumes of different color materials for the restoration, which can be used to manufacture the restoration by 3D printing or other processes such as milling. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a block diagram of a system for designing a customized dental restoration. [Figure 2] FIG. 1 is an illustration of a process for designing a customized dental restoration. [Figure 3] Shown is vestibular veneering. [Figure 4] 1 shows a posterization of a color distribution map for a dental restoration. [Figure 5] 10 illustrates the replacement of grayscale values with false color for posterization. [Figure 6] 1 illustrates the selection of color segment boundaries and their export to a scalable vector graphic file. [Figure 7] 1 shows the application of a color distribution map as a texture to a tooth. [Figure 8] This shows the placement of a scalable vector graphic file in a dental restoration screen. [Figure 9] Demonstrates conforming extensible vector graphics splines to 3D geometry. [Figure 10] Shows reduction of outer surface. [Figure 11] 10 illustrates cutting an outer surface using an extruded, scalable vector graphic path. [Figure 12] 10 shows the resulting 3D model with volumes of different color materials to provide color transition zones. DETAILED DESCRIPTION OF THE INVENTION

[0006] The method for creating color-customized restorations requires color and shape information in a format that can be used to create the restoration. The method described herein can create such data from different measurement sources and create such color customization files in an automated or semi-automated manner. Thus, the method can be used in a full color customization digital workflow for color processing of ceramics and composites, or other materials. The method combines color, color distribution maps, and shapes to create a three-dimensional (3D) model for a fully customized dental restoration, such as a crown, veneer, bridge, or other restoration. The 3D model can include segments that can be used to additively manufacture (3D print) certain materials. The 3D model can also be used to fabricate customized restorations by other processes, such as milling or combined / hybrid processes (e.g., 3D printing a customized layered block and milling the desired restoration). Further processes can include molding, forming and pressing ceramics, layering glass-ceramics, and milling with grinding.

[0007] 1 is a block diagram of a system for designing a customized dental restoration. The system includes a processor 10 that receives inputs 16, described below, to manufacture the customized dental restoration and provide a color customization output 18. The system may also include an electronic display device 14, such as a liquid crystal display (LCD) device, and an input device 12 for receiving user commands or other information. The system may be implemented, for example, on a desktop, notebook, or tablet computer.

[0008] 2 is a diagram of a process for designing a customized dental restoration using a full digital color workflow. This process, including the steps described further below, can be implemented in software or firmware for execution by a processor, such as, for example, processor 10. This process can also be automated using a processor operating under software control.

[0009] The data processing is based on different input measurement data, such as a photograph 20 with posterization, a color shade guide 22, a color distribution map with colors 24, a shape 26 from a physical (plaster) model or intraoral scan, and a color distribution map with colors and shapes 28. The processing compiles the collected information into a 3D model containing geometry and color information, as follows: assigning colors to the color distribution map using the shade guide or posterization (step 30); assigning colors and the color distribution map to shapes (step 32); calculating a digital color three-dimensional (3D) model (step 34); and optionally, visualization and simulation (step 36). The result is a color customization output 38 file or data structure containing the digital color 3D model; the structure of such a file or data structure may vary depending on the type of individualization and production process. One example is vestibular veneers, which are a common type of process for dental technicians to manually create aesthetic restorations.

[0010] FIG. 3 shows a vestibular veneer article. Part 4 is a vestibular veneer article that is scaled down according to the different colored parts (1, 2, 3) on the vestibular side. The transition zone between the color layers is characterized by a graded layer thickness from one color layer and a reduced layer thickness from the second color layer material. This appears to the observer as a smooth transition between the layers. There are other layering techniques that can be used in addition to or instead of this for greater aesthetic individualization.

[0011] The actual appearance of the resulting restoration depends on the color distribution map and its actual color. To achieve a natural appearance and correct color in each segment of the restoration, the process or workflow must take into account that color depends on the color of the tooth's residual root, the color within the layer, and the layer thickness and their translucency characteristics. Based on the desired color information for each color segment, the thickness and required color of each layer can be estimated. For example, the desired A1 color is obtained from the combination of the corresponding color ND2, a 0.4 mm layer thickness, and the LT A1 veneer material. In this case, the 0.4 mm layer thickness can be used to obtain the A1 color on the appropriate color segment. Other color segments can be treated in the same manner. Color transition zones can be used to prevent abrupt color changes due to non-perpendicular cuts between veneer (e.g., outer surface) materials. Depending on the size of the color transition zone, the corresponding cutting angle can be determined or set.

[0012] To create a digital 3D model of the oral vestibular veneer structure from the collected data, the following process can be used, which can be automated using software processing by the processor 10.

[0013] Step 1. Figure 4 illustrates posterizing a color distribution map and extracting a color distribution map of a tooth 40 for a dental restoration. In particular, this process involves posterizing a digital photograph (photo) or other digital representation of the tooth to extract a color distribution map of the tooth, as described, for example, in U.S. Patent No. 10,245,126. The result (image 42) provides a color distribution map of the tooth 40, which is location information for the tooth color.

[0014] Step 2 (Optional): Figure 5 shows optional replacement of grayscale values with false colors for posterization. In this optional case, the posterization process uses a digital photograph to extract color information and optionally assigns false colors (e.g., blue, green, yellow, as represented by different types of cross-hatching) to make the grayscale color differences of the teeth more visually apparent.

[0015] Step 3. Figure 6 shows the selection of boundaries of color segments (image 44) in a digitally posterized tooth (as shown in Figures 4 and 5) or other posterized digital representation of a tooth, and their export to a scalable vector graphics (SVG) file 46 or other type of data structure. The boundaries can be determined by detecting the location of transitions between colors, grayscale values, or false colors in a color distribution map.

[0016] Step 4 (Optional): Figure 7 shows the application of a color distribution map (image 48) as a texture (image 50) to the digitally posterized teeth shown in Figures 4 and 5. The texture is optional and provides a combination of the digital 3D shape and the color distribution map.

[0017] Step 5. Figure 8 shows pasting the SVG file onto the dental restoration screen, and in particular combining the SVG file with the boundaries of the color segments in the digitally posterized tooth.

[0018] Step 6. Figure 9 shows matching the SVG file splines to the digital 3D geometry or shape data of the teeth. The 3D shape data can be obtained from scanning a physical model of the teeth or from an intraoral scan of the teeth to create a corresponding digital 3D model of the teeth. The SVG splines are obtained as shown in Figure 6, and the splines from the posterized photo or digital representation of the teeth are matched to corresponding positions in the digital 3D model of the teeth, as shown in Figure 9.

[0019] Step 7. Figure 10 shows the reduction of the outer surface from the digital 3D model shown in Figure 9 to accommodate the color segments. The outer surface is reduced by an amount desired or necessary to accommodate the color segments representing the different materials for the restoration, for example, reduced to accommodate a layer thickness of 0.4 mm for the A1 color, as described above.

[0020] Step 8. Figure 11 illustrates using an extruded SVG path to cut the outer surface of the digital 3D model (shown in Figure 9) to convert the digital surface model (image 52) into a digital volumetric 3D model (image 54). In particular, the SVG path is extruded through the digital 3D surface model to create a volume and a resulting digital 3D volumetric model. The SVG path can, for example, be extruded in a non-orthogonal direction relative to the surface of the digital 3D model. The volume of the digital 3D model can then be used, for example, to 3D print a corresponding restoration. The volume of the 3D model can also be a source for a best fit to find the optimal location of a part within a color-toned composite mill blank. In particular, one approach is to use the designed color structure to find the closest possible location within a composite laminate mill blank by a best fit algorithm to mill the best possible color match for an aesthetic dental restoration.

[0021] 12 shows the resulting digital color 3D model with volumes of different color materials to provide color transition zones, e.g., three volumes of three different colors (image 56), one volume of one color (image 58), and two volumes of two different colors (image 60). The color volumes are represented by different cross-hatching in the image. This digital 3D model can be used to 3D print the corresponding restoration.

[0022] Table 1 summarizes this process for manufacturing a digital 3D model for a customized color dental restoration. These steps can be implemented in software for execution by a processor that automatically performs the steps of creating the digital 3D model from input. The process can optionally include user input, such as a user entering information via input device 12 and viewing either a digital representation or a digital 3D model via display device 14. [Table 1]

Claims

1. 1. A computer-implemented method for creating a color 3D model for a dental restoration, the method being executed by a processor, comprising: receiving tooth color information, a color distribution map, and a shape; assigning said color information to said color distribution map; combining the assigned color information and the color distribution map with the shape; creating a digital color 3D model based on the assigned color information and the color distribution map combined with the shape; A method comprising:

2. The method of claim 1 , wherein the receiving step includes posterizing the tooth photo to extract the color distribution map.

3. The method of claim 2 , wherein the posterizing further comprises replacing grayscale values ​​in the color distribution map with false colors.

4. The method of claim 1 , wherein the allocating step comprises selecting a boundary of a segment of the color information in the color distribution map and exporting the boundary using a spline of the segment.

5. The method of claim 4 further comprising applying the spline to the color distribution map.

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