Color matching method for a color-changing denture

Abstract

The application belongs to the technical field of false tooth preparation, and provides a color matching preparation method of color-changing false tooth, which comprises the following steps: acquiring a crown image; preparing the color-changing false tooth; and matching the color of the color-changing false tooth according to the crown image to obtain the color-matched false tooth. When the color-changing false tooth is irradiated by ultraviolet light, the color-changing false tooth is adaptively adjusted according to the color depth change trend of the tooth color gradient to adapt to the adjacent tooth, so that the color difference between the color-matched color-changing false tooth and the adjacent tooth is minimized. The approximate time period of stopping irradiation can be accurately judged through colored state conversion calculation time, and a slight increase in irradiation time is added to improve the stability of the colored state substance with the minimum color difference from the adjacent tooth, so that the actual use requirement can be better met, and the photochromic material is more stable in the colored state with the minimum color difference from the adjacent tooth.

Description

Technical Field

[0001] This invention belongs to the fields of denture fabrication technology and intelligent manufacturing technology, specifically a method for color matching and fabrication of color-changing dentures. Background Technology

[0002] Currently, to improve the aesthetics of denture surfaces, the demand for color-changing dentures is increasing. Color-changing dentures are generally made using photochromic materials. These materials exhibit reversible photoisomerization when irradiated with light of an appropriate wavelength. Photochromism refers to a process where a compound A, when exposed to light of a specific wavelength, undergoes a photochemical reaction to produce product B. The colors (i.e., light absorption) of A and B are significantly different, as illustrated in the photochromic compound in patent application CN114767549A. Product B can revert to its original form A under irradiation with another beam of light or after heating. Photochromism is a reversible chemical reaction; it refers to materials that change color upon excitation by a light source.

[0003] However, in the manufacture of dentures, due to the reversible process of photochromic materials changing their absorption spectrum after being exposed to light, discolored teeth generally change between two or more states, such as the change between compound A and product B. When the tooth color changes, one of the states will inevitably be completely different from the original tooth color. Since many discoloration materials generally require a coloring or fading time of several minutes or hours, this makes the color matching method for dentures feasible. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing color-changing dentures, in order to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0005] To achieve the above objectives, this invention proposes a method for preparing color-changing dentures, specifically including the following steps:

[0006] S1, acquire image of the tooth crown;

[0007] S2, Preparation of discolored dentures;

[0008] S3, matching the color of the discolored denture with the crown image to obtain the matched denture.

[0009] Furthermore, in S1, the crown image is obtained by taking pictures of the patient's crown using a dental camera, intraoral camera, CCD camera, or digital camera.

[0010] Furthermore, in S2, the method for preparing discolored dentures includes:

[0011] Three-dimensional data of plaster molds or dental impressions of the patient's oral cavity are collected using an extraoral scanner;

[0012] Alternatively, a three-dimensional data scan of the patient's oral cavity can be performed directly using an intraoral scanner to obtain the patient's oral cavity data.

[0013] The three-dimensional data of the patient's oral cavity is used to design a denture mold and then transmitted to a 3D printer for printing to obtain a printed denture mold;

[0014] Based on the three-dimensional data of the patient's oral cavity, the printed denture mold is ground using a grinding machine to obtain the denture mold;

[0015] Color-changing dentures are made by injecting denture material into a denture mold.

[0016] Dental materials include dental fillers and light-sensitive resins;

[0017] The dental filler has a weight percentage of 0-70 wt%; the photosensitive resin has a weight percentage of 30-100 wt%.

[0018] Dental fillers include any one or more combinations of zirconium oxide, silica, titanium dioxide, and polymethyl methacrylate; the particle size range of dental fillers is 3–25 μm;

[0019] Photosensitive resin materials include acrylate resin or UV-curable resin, UV curing agent, benzophenone, 2,6-di-tert-butyl-p-cresol, UV absorber, and photochromic material; (wherein, the acrylate resin is a polymerizable acrylate resin, and under light irradiation, the UV curing agent enables the unsaturated olefin bonds in the acrylate resin to undergo a polymerization reaction to generate a composite material with mechanical properties and strength. The UV curing agent absorbs energy of a certain wavelength of light to generate a large number of free radicals, thereby initiating an addition polymerization reaction of the unsaturated olefin bonds in the acrylate resin). The UV curing agent is any one of benzophenone, 2,4-dihydroxybenzophenone, and α-diketone.

[0020] The photochromic material is any one of diarylethylene compounds, 1,2-bis(2,4-dimethyl-5-phenyl-3-thiophene)-3,3,4,4,5,5-hexafluorocyclopentene, triarylmethane compounds, and spiropyran photochromic compounds. (The photochromic mechanism of these photochromic materials is a pericyclic reaction, that is, under ultraviolet light excitation, the diarylethylene compound rotates to form a colored closed ring, and the closed ring undergoes the opposite change under visible light irradiation. After light exposure, its structure changes, resulting in a color change. Therefore, these photochromic materials are used as dyes for color-changing dentures, so that these color-changing dentures have a certain color before use. After curing by light of a specific wavelength, the color of the dental composite material changes to a final color different from the initial color.)

[0021] Preferably, in S2, the method for preparing the discoloration denture includes any one of the methods disclosed in CN104983477B, CN112430074A, and CN112223749B, wherein the material of the discoloration denture includes any one of CN114767549A, CN114767549A, CN105167869A, and CN105832563A, wherein the material of the discoloration denture includes a photochromic material.

[0022] Because the photochromic material in color-changing dentures requires a certain period of ultraviolet (UV) light exposure to transform it into a colored state, and this exposure process is a gradual color change, the color varies with the duration of UV exposure. The longer the UV exposure, the more of the photochromic material transforms into a colored state, resulting in a deeper color. However, if the color is too dark, it may not match the adjacent teeth (the teeth next to where the color-changing denture will be installed). Therefore, the following methods are needed to control the duration of UV exposure to ensure a gradual color change that matches the adjacent teeth:

[0023] Furthermore, in S3, the method for obtaining a matched denture by matching the color of the discolored denture based on the crown image includes:

[0024] The surface of the discolored dentures was irradiated with ultraviolet light in the wavelength range of 150nm to 350nm. (The diarylethene compounds in the photochromic materials, such as 1,2-bis(2,5-dimethylthiophen-3-yl)perfluorocyclopentene, cause the discolored dentures to appear pink under ultraviolet light excitation, while 1,2-bis(2,4-dimethyl-5-phenyl-3-thiophene)-3,3,4,4,5,5-hexafluoro-1-cyclopentene appears blue after ultraviolet light irradiation. However, irradiation of the photochromic material in the discolored dentures with ultraviolet light for a certain period of time causes the photochromic material to become colored, and this process is reversible. In clinical use, the colored photochromic material requires irradiation with visible light greater than 400nm for a certain period of time to change from a colored state to a colorless state.)

[0025] Using a crown image as a reference image, the reference image is segmented using a watershed algorithm or edge detection operator to obtain multiple image regions. In each image region of the reference image, the grayscale images of two adjacent teeth are marked as two adjacent tooth images (the image regions of the patient's teeth in the reference image are selected). The average grayscale values ​​of all pixels in the two adjacent tooth images are Gray1 and Gray2, respectively, and the absolute value of the difference between Gray1 and Gray2 is GrayGap.

[0026] The CCD camera acquires images of the discolored dentures in real time as the target images, with the moment when ultraviolet light irradiation of the surface of the discolored dentures begins to be T0; the time interval for the CCD camera to acquire the target images is time1.

[0027] The target image is segmented into multiple image regions using the watershed algorithm or edge detection operator. The grayscale image of the discolored denture is marked in each image region of the target image as the denture image. (If the average grayscale value of the image region is within the preset grayscale value range, the image region is a denture sub-image.) Alternatively, the grayscale image of the discolored denture in the target image is identified using the YOLO object detection algorithm as the denture image.

[0028] Starting from time T0, real-time acquisition of denture images is performed. If the average gray value of all pixels in the denture image at the current time TC, Gray(TC), satisfies the condition: |Gray(TC)-Mean(Gray1,Gray2)|≤GrayGap, then the ultraviolet light irradiation on the surface of the discolored denture is stopped, thereby obtaining the matched denture. Here, Mean(Gray1,Gray2) is the average value of Gray1 and Gray2.

[0029] The beneficial effect is that when the discolored denture is irradiated with ultraviolet light, the color difference between the discolored denture and the adjacent teeth can be minimized by adaptively adjusting the discolored denture to match the adjacent teeth according to the color depth change trend of the tooth color.

[0030] Although the above solutions minimize the color difference between the color-changing dentures and adjacent teeth, the color change caused by ultraviolet light remains. Since the photochromic material's transition to a colored state is reversible, exposure to visible light (greater than 400nm) for a certain period will still cause the colored state to revert to a colorless state. Therefore, in practice, a slightly longer exposure time is needed to improve the stability of the colored material with the smallest color difference from adjacent teeth to meet practical needs. This requires making the photochromic material more stable in its color-difference-minimizing state, increasing the time required for the colored state to transition to a colorless state to meet actual service life requirements, and extending the actual time needed for subsequent color adjustments. To meet these requirements, the present invention proposes the following preferred solutions:

[0031] Preferably, in S3, the method for matching the color of the discolored denture based on the crown image to obtain the matched denture includes:

[0032] The surface of the discolored dentures was irradiated with ultraviolet light in the wavelength range of 150nm to 350nm;

[0033] Using a crown image as a reference image, the reference image is segmented using a watershed algorithm or edge detection operator to obtain multiple image regions. In each image region of the reference image, the grayscale images of two adjacent teeth are marked as two adjacent tooth images (the image regions of the patient's teeth in the reference image are selected). The average grayscale values ​​of all pixels in the two adjacent tooth images are Gray1 and Gray2, respectively, and the absolute value of the difference between Gray1 and Gray2 is GrayGap.

[0034] The CCD camera acquires images of the discolored dentures in real time as the target images, with the moment when ultraviolet light irradiation of the surface of the discolored dentures begins to be T0; the time interval for the CCD camera to acquire the target images is time1.

[0035] The target image is segmented into multiple image regions using the watershed algorithm or edge detection operator. The grayscale image of the discolored denture is marked in each image region of the target image as the denture image. (If the average grayscale value of the image region is within the preset grayscale value range, the image region is a denture sub-image.) Alternatively, the grayscale image of the discolored denture in the target image is identified using the YOLO object detection algorithm as the denture image.

[0036] Starting from time T0, real-time acquisition of denture images is performed. If the average grayscale value of all pixels in the denture image at time TC, Gray(TC), satisfies the condition |Gray(TC)-Mean(Gray1,Gray2)|≤GrayGap, the calculation time tNext for the next chromatic state transition at time TC is calculated.

[0037]

[0038] Alternatively, tNext = tCurrent + TMaxGray × PAT;

[0039] PAT=GaryG(TC-i×time1) / TGrayAVE;

[0040] Take all the denture images acquired from time T0 to the current time TC-time1 to form sequence Map1. Let the average gray value of all pixels in the denture image be MaAVE. Select all denture images in sequence Map1 whose absolute value of the difference between each MaAVE and Gray(TC) is less than or equal to GrayGap to form sequence Map2.

[0041] Then tCurrent is the acquisition time of the denture image in the sequence Map2 that is closest to the current time TC; or, tCurrent is the acquisition time of the denture image that is closest to the current time TC and satisfies that the average of all gray values ​​is less than or equal to |Gray(TC)-Gray(TC-time1)|.

[0042] TMaxGray is the maximum time interval between any two adjacent denture images in sequence Map2.

[0043] TGrayAVE is the average time interval between each pair of adjacent denture images in sequence Map2.

[0044] Where i is a variable, N is the number of denture images in sequence Map2, and PAT is the gradient color difference ratio;

[0045] GaryG(TC-i×time1) is the i-th gradient color difference interval. The calculation method of GaryG(TC-i×time1) is as follows: take the sequence closest to time TC-i×time1 in the reverse time order and satisfy the average value of all gray values ​​being less than or equal to |Gray(TC)-Gray(TC-time1)|. The acquisition time of the denture image in Map2 is T1, then GaryG(TC-i×time1) is the duration from time T1 to time TC-i×time1.

[0046] Where Gray(TC-time1) is the average gray value of all pixels in the denture image at time TC-time1;

[0047] Where Mean(Gray1,Gray2) is the average of Gray1 and Gray2;

[0048] Starting from the current time TC, continue to irradiate the surface of the color-changing denture with ultraviolet light. If the average gray value of all pixels in the acquired denture image is less than or equal to GrayGap within the time tNext from TC to the color state conversion calculation time, then stop irradiating the surface of the color-changing denture with ultraviolet light to obtain the matched denture; otherwise, stop irradiating the surface of the color-changing denture with ultraviolet light at the time tNext to obtain the matched denture.

[0049] Beneficial effects: The calculation time of the colored state transformation in the above scheme can accurately determine the approximate time period for stopping irradiation. Slightly increasing the irradiation time can improve the stability of the colored substance with the smallest color difference from the adjacent tooth, which can better meet the actual use needs and make the photochromic material more stable in the colored state with the smallest color difference from the adjacent tooth.

[0050] The process of irradiating the surface of the discolored denture with ultraviolet light in the wavelength range of 150nm to 350nm involves irradiating the surface of the discolored denture with any one of the following: a high-intensity ultraviolet high-pressure mercury lamp, a high-intensity metal halide lamp, a photolithography lamp, a capillary ultra-high-pressure mercury lamp, a photo-cleaning lamp, a CD-ROM lamp, an ultraviolet iron lamp, a sterilization lamp, a short-arc xenon lamp, or an excimer discharge lamp.

[0051] This invention also provides a color matching and preparation system for color-changing dentures. The system includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the color matching and preparation method for color-changing dentures. The system can run on computing devices such as desktop computers, laptops, handheld computers, and cloud data centers. The runnable system may include, but is not limited to, processors, memory, and server clusters. The processor executes the computer program within the following system units:

[0052] Image acquisition unit, used to acquire images of the tooth crown;

[0053] Adjust the color matching unit to match the color of the discolored dentures based on the crown image.

[0054] The beneficial effects of this invention are as follows: This invention provides a method for preparing color-changing dentures, which has the following advantages: When the color-changing denture is irradiated with ultraviolet light, the color-changing denture is adaptively adjusted to match the adjacent teeth according to the color depth change trend of the tooth color. This minimizes the color difference between the matched color-changing denture and the adjacent teeth. By calculating the time of the color state transformation, the approximate time period for stopping irradiation can be accurately determined. By slightly increasing the irradiation time, the stability of the colored material with the smallest color difference with the adjacent teeth can be improved, which better meets the actual use requirements and makes the photochromic material more stable in the colored state with the smallest color difference with the adjacent teeth. Attached Figure Description

[0055] The above and other features of the present invention will become more apparent from the detailed description of the embodiments shown in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals denote the same or similar elements. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort. In the drawings:

[0056] Figure 1 A flowchart illustrating a method for preparing color-changing dentures;

[0057] Figure 2This is a structural diagram of a color matching preparation system for color-changing dentures. Detailed Implementation

[0058] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The same reference numerals used throughout the accompanying drawings indicate the same or similar parts.

[0059] like Figure 1 The diagram shows a flowchart of a method for preparing color-changing dentures according to the present invention. Figure 1 This paper describes a method for preparing color-changing dentures according to an embodiment of the present invention, with a detailed description of preferred embodiments. It should be emphasized that the following description is merely exemplary and not intended to limit the scope or application of the invention.

[0060] S1, acquire image of the tooth crown;

[0061] S2, Preparation of discolored dentures;

[0062] S3, matching the color of the discolored denture with the crown image to obtain the matched denture.

[0063] Furthermore, in S1, the crown image is obtained by taking pictures of the patient's crown using a dental camera, intraoral camera, CCD camera, or digital camera.

[0064] Furthermore, in S2, the method for preparing discolored dentures includes:

[0065] Three-dimensional data of plaster molds or dental impressions of the patient's oral cavity are collected using an extraoral scanner;

[0066] Alternatively, a three-dimensional data scan of the patient's oral cavity can be performed directly using an intraoral scanner to obtain the patient's oral cavity data.

[0067] The three-dimensional data of the patient's oral cavity is used to design a denture mold and then transmitted to a 3D printer for printing to obtain a printed denture mold;

[0068] Based on the three-dimensional data of the patient's oral cavity, the printed denture mold is ground using a grinding machine to obtain the denture mold;

[0069] Color-changing dentures are made by injecting denture material into a denture mold.

[0070] Dental materials include dental fillers and light-sensitive resins;

[0071] The dental filler has a weight percentage of 0-70 wt%; the photosensitive resin has a weight percentage of 30-100 wt%.

[0072] Dental fillers include any one or more combinations of zirconium oxide, silica, titanium dioxide, and polymethyl methacrylate; the particle size range of dental fillers is 3–25 μm;

[0073] Photosensitive resin materials include acrylate resin or UV-curable resin, UV curing agent, benzophenone, 2,6-di-tert-butyl-p-cresol, UV absorber, and photochromic material; (wherein, the acrylate resin is a polymerizable acrylate resin, and under light irradiation, the UV curing agent enables the unsaturated olefin bonds in the acrylate resin to undergo a polymerization reaction to generate a composite material with mechanical properties and strength. The UV curing agent absorbs energy of a certain wavelength of light to generate a large number of free radicals, thereby initiating an addition polymerization reaction of the unsaturated olefin bonds in the acrylate resin). The UV curing agent is any one of benzophenone, 2,4-dihydroxybenzophenone, and α-diketone.

[0074] The photochromic material is any one of diarylethylene compounds, 1,2-bis(2,4-dimethyl-5-phenyl-3-thiophene)-3,3,4,4,5,5-hexafluorocyclopentene, triarylmethane compounds, and spiropyran photochromic compounds. (The photochromic mechanism of these photochromic materials is a pericyclic reaction, that is, under ultraviolet light excitation, the diarylethylene compound rotates to form a colored closed ring, and the closed ring undergoes the opposite change under visible light irradiation. After light exposure, its structure changes, resulting in a color change. Therefore, these photochromic materials are used as dyes for color-changing dentures, so that these color-changing dentures have a certain color before use. After curing by light of a specific wavelength, the color of the dental composite material changes to a final color different from the initial color.)

[0075] Preferably, in S2, the method for preparing the discoloration denture includes any one of the methods disclosed in CN104983477B, CN112430074A, and CN112223749B, wherein the material of the discoloration denture includes any one of CN114767549A, CN114767549A, CN105167869A, and CN105832563A, wherein the material of the discoloration denture includes a photochromic material.

[0076] Because the photochromic material in color-changing dentures requires a certain period of ultraviolet (UV) light exposure to transform it into a colored state, and this exposure process is a gradual color change, the color varies with the duration of UV exposure. The longer the UV exposure, the more of the photochromic material transforms into a colored state, resulting in a deeper color. However, if the color is too dark, it may not match the adjacent teeth (the teeth next to where the color-changing denture will be installed). Therefore, the following methods are needed to control the duration of UV exposure to ensure a gradual color change that matches the adjacent teeth:

[0077] Furthermore, in S3, the method for obtaining a matched denture by matching the color of the discolored denture based on the crown image includes:

[0078] The surface of the discolored dentures was irradiated with ultraviolet light in the wavelength range of 150nm to 350nm. (The diarylethene compounds in the photochromic materials, such as 1,2-bis(2,5-dimethylthiophen-3-yl)perfluorocyclopentene, cause the discolored dentures to appear pink under ultraviolet light excitation, while 1,2-bis(2,4-dimethyl-5-phenyl-3-thiophene)-3,3,4,4,5,5-hexafluoro-1-cyclopentene appears blue after ultraviolet light irradiation. However, irradiation of the photochromic material in the discolored dentures with ultraviolet light for a certain period of time causes the photochromic material to become colored, and this process is reversible. In clinical use, the colored photochromic material requires irradiation with visible light greater than 400nm for a certain period of time to change from a colored state to a colorless state.)

[0079] Using a crown image as a reference image, the reference image is segmented using a watershed algorithm or edge detection operator to obtain multiple image regions. In each image region of the reference image, the grayscale images of two adjacent teeth are marked as two adjacent tooth images (the image regions of the patient's teeth in the reference image are selected). The average grayscale values ​​of all pixels in the two adjacent tooth images are Gray1 and Gray2, respectively, and the absolute value of the difference between Gray1 and Gray2 is GrayGap.

[0080] The CCD camera acquires images of the discolored dentures in real time as the target images, with the moment when ultraviolet light irradiation of the surface of the discolored dentures begins to be T0; the time interval for the CCD camera to acquire the target images is time1.

[0081] The target image is segmented into multiple image regions using the watershed algorithm or edge detection operator. The grayscale image of the discolored denture is marked in each image region of the target image as the denture image. (If the average grayscale value of the image region is within the preset grayscale value range, the image region is a denture sub-image.) Alternatively, the grayscale image of the discolored denture in the target image is identified using the YOLO object detection algorithm as the denture image.

[0082] Starting from time T0, real-time acquisition of denture images is performed. If the average gray value of all pixels in the denture image at the current time TC, Gray(TC), satisfies the condition: |Gray(TC)-Mean(Gray1,Gray2)|≤GrayGap, then the ultraviolet light irradiation on the surface of the discolored denture is stopped, thereby obtaining the matched denture. Here, Mean(Gray1,Gray2) is the average value of Gray1 and Gray2.

[0083] The beneficial effect is that when the discolored denture is irradiated with ultraviolet light, the color difference between the discolored denture and the adjacent teeth can be minimized by adaptively adjusting the discolored denture to match the adjacent teeth according to the color depth change trend of the tooth color.

[0084] Although the above solutions minimize the color difference between the color-changing dentures and adjacent teeth, the color change caused by ultraviolet light remains. Since the photochromic material's transition to a colored state is reversible, exposure to visible light (greater than 400nm) for a certain period will still cause the colored state to revert to a colorless state. Therefore, in practice, a slightly longer exposure time is needed to improve the stability of the colored material with the smallest color difference from adjacent teeth to meet practical needs. This requires making the photochromic material more stable in its color-difference-minimizing state, increasing the time required for the colored state to transition to a colorless state to meet actual service life requirements, and extending the actual time needed for subsequent color adjustments. To meet these requirements, the present invention proposes the following preferred solutions:

[0085] Preferably, in S3, the method for matching the color of the discolored denture based on the crown image to obtain the matched denture includes:

[0086] The surface of the discolored dentures was irradiated with ultraviolet light in the wavelength range of 150nm to 350nm;

[0087] Using a crown image as a reference image, the reference image is segmented using a watershed algorithm or edge detection operator to obtain multiple image regions. In each image region of the reference image, the grayscale images of two adjacent teeth are marked as two adjacent tooth images (the image regions of the patient's teeth in the reference image are selected). The average grayscale values ​​of all pixels in the two adjacent tooth images are Gray1 and Gray2, respectively, and the absolute value of the difference between Gray1 and Gray2 is GrayGap.

[0088] The CCD camera acquires images of the discolored dentures in real time as the target images, with the moment when ultraviolet light irradiation of the surface of the discolored dentures begins to be T0; the time interval for the CCD camera to acquire the target images is time1.

[0089] The target image is segmented into multiple image regions using the watershed algorithm or edge detection operator. The grayscale image of the discolored denture is marked in each image region of the target image as the denture image. (If the average grayscale value of the image region is within the preset grayscale value range, the image region is a denture sub-image.) Alternatively, the grayscale image of the discolored denture in the target image is identified using the YOLO object detection algorithm as the denture image.

[0090] Starting from time T0, real-time acquisition of denture images is performed. If the average grayscale value of all pixels in the denture image at time TC, Gray(TC), satisfies the condition |Gray(TC)-Mean(Gray1,Gray2)|≤GrayGap, the calculation time tNext for the next chromatic state transition at time TC is calculated.

[0091]

[0092] Alternatively, tNext = tCurrent + TMaxGray × PAT;

[0093] PAT=GaryG(TC-i×time1) / TGrayAVE;

[0094] Take all the denture images acquired from time T0 to the current time TC-time1 to form sequence Map1. Let the average gray value of all pixels in the denture image be MaAVE. Select all denture images in sequence Map1 whose absolute value of the difference between each MaAVE and Gray(TC) is less than or equal to GrayGap to form sequence Map2.

[0095] Then tCurrent is the acquisition time of the denture image in the sequence Map2 that is closest to the current time TC; or, tCurrent is the acquisition time of the denture image that is closest to the current time TC and satisfies that the average of all gray values ​​is less than or equal to |Gray(TC)-Gray(TC-time1)|.

[0096] TMaxGray is the maximum time interval between any two adjacent denture images in sequence Map2.

[0097] TGrayAVE is the average time interval between each pair of adjacent denture images in sequence Map2;

[0098] Where i is a variable, N is the number of denture images in sequence Map2, and PAT is the gradient color difference ratio;

[0099] GaryG(TC-i×time1) is the i-th gradient color difference interval. The calculation method of GaryG(TC-i×time1) is as follows: take the sequence closest to time TC-i×time1 in the reverse time order and satisfy the average value of all gray values ​​being less than or equal to |Gray(TC)-Gray(TC-time1)|. The acquisition time of the denture image in Map2 is T1, then GaryG(TC-i×time1) is the duration from time T1 to time TC-i×time1.

[0100] Where Gray(TC-time1) is the average gray value of all pixels in the denture image at time TC-time1;

[0101] Where Mean(Gray1,Gray2) is the average of Gray1 and Gray2;

[0102] Starting from the current time TC, continue to irradiate the surface of the color-changing denture with ultraviolet light. If the average gray value of all pixels in the acquired denture image is less than or equal to GrayGap within the time tNext from TC to the color state conversion calculation time, then stop irradiating the surface of the color-changing denture with ultraviolet light to obtain the matched denture; otherwise, stop irradiating the surface of the color-changing denture with ultraviolet light at the time tNext to obtain the matched denture.

[0103] Beneficial effects: The calculation time of the colored state transformation in the above scheme can accurately determine the approximate time period for stopping irradiation. Slightly increasing the irradiation time can improve the stability of the colored substance with the smallest color difference from the adjacent tooth, which can better meet the actual use needs and make the photochromic material more stable in the colored state with the smallest color difference from the adjacent tooth.

[0104] The process of irradiating the surface of the discolored denture with ultraviolet light in the wavelength range of 150nm to 350nm involves irradiating the surface of the discolored denture with any one of the following: a high-intensity ultraviolet high-pressure mercury lamp, a high-intensity metal halide lamp, a photolithography lamp, a capillary ultra-high-pressure mercury lamp, a photo-cleaning lamp, a CD-ROM lamp, an ultraviolet iron lamp, a sterilization lamp, a short-arc xenon lamp, or an excimer discharge lamp.

[0105] An embodiment of the present invention provides a color matching preparation system for color-changing dentures, such as... Figure 2 As shown, a color-matching fabrication system for color-changing dentures according to this embodiment includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the above-described embodiment of the color-matching fabrication method for color-changing dentures. The processor executes the computer program within the following system units:

[0106] Image acquisition unit, used to acquire images of the tooth crown;

[0107] Adjust the color matching unit to match the color of the discolored dentures based on the crown image.

[0108] The color matching preparation system for a color-changing denture includes: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps in the above-described embodiment of the color matching preparation method for a color-changing denture. The color matching preparation system for a color-changing denture can run on computing devices such as desktop computers, laptops, handheld computers, and cloud data centers. The runnable system may include, but is not limited to, processors, memory, and server clusters.

[0109] The color matching and fabrication system for color-changing dentures described above can run on computing devices such as desktop computers, laptops, handheld computers, and cloud data centers. The system includes, but is not limited to, a processor and a memory. Those skilled in the art will understand that the example described is merely an illustration of a method for color matching and fabrication of color-changing dentures and does not constitute a limitation on such a method. It may include more or fewer components, or combine certain components, or use different components. For example, the system may also include input / output devices, network access devices, buses, etc.

[0110] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete component gate circuits, transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the color-matching preparation system for color-changing dentures, connecting various sub-regions of the system via various interfaces and lines.

[0111] The memory can be used to store the computer program and / or modules. The processor implements various functions of the color matching preparation method for color-changing dentures by running or executing the computer program and / or modules stored in the memory, and by calling the data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, phonebook, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital card (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0112] Although the invention has been described in considerable detail and particularly with regard to several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment, thereby effectively covering the intended scope of the invention. Furthermore, the invention has been described above with respect to embodiments foreseeable by the inventors in order to provide a useful description, and non-substantial modifications to the invention that have not yet been foreseen may still represent equivalent modifications.

Claims

1. A method for preparing color-changing dentures, characterized in that, The method includes the following steps: S1, acquire image of the tooth crown; S2, Preparation of discolored dentures; S3, Match the color of the discolored denture with the crown image to obtain the matched denture; In S3, the method for obtaining a matched color denture by matching the color of the discolored denture based on the crown image includes: The surface of the discolored dentures was irradiated with ultraviolet light in the wavelength range of 150nm to 350nm; Using a crown image as a reference image, the reference image is segmented using a watershed algorithm or an edge detection operator to obtain multiple image regions. In each image region of the reference image, the grayscale images of two adjacent teeth are marked as two adjacent tooth images. The average grayscale values ​​of all pixels in the two adjacent tooth images are Gray1 and Gray2, respectively, and the absolute value of the difference between Gray1 and Gray2 is denoted as GrayGap. The CCD camera acquires images of the discolored dentures in real time as the target images, with the moment when ultraviolet light irradiation of the surface of the discolored dentures begins to be T0; the time interval for the CCD camera to acquire the target images is time1. The target image is segmented into multiple image regions using the watershed algorithm or edge detection operator. The grayscale image of the discolored denture is marked in each image region of the target image as the denture image. Alternatively, the grayscale image of the discolored denture in the target image is identified by the YOLO object detection algorithm as the denture image. Starting from time T0, real-time acquisition of denture images is performed. If the average grayscale value of all pixels in the denture image at time TC, Gray(TC), satisfies the condition |Gray(TC)-Mean(Gray1,Gray2)|≤GrayGap, the calculation time tNext for the next chromatic state transition at time TC is calculated. ； Alternatively, tNext = tCurrent + TMaxGray × PAT; PAT=GaryG(TC-i×time1) / TGrayAVE; Take all the denture images acquired from time T0 to the current time TC-time1 to form sequence Map1. Let the average gray value of all pixels in the denture image be MaAVE. Select all denture images in sequence Map1 whose absolute value of the difference between each MaAVE and Gray(TC) is less than or equal to GrayGap to form sequence Map2. Then tCurrent is the acquisition time of the denture image in the sequence Map2 that is closest to the current time TC; or, tCurrent is the acquisition time of the denture image that is closest to the current time TC and satisfies that the average of all gray values ​​is less than or equal to |Gray(TC)-Gray(TC-time1)|. TMaxGray is the maximum time interval between any two adjacent denture images in sequence Map2. TGrayAVE is the average time interval between each pair of adjacent denture images in sequence Map2; Where i is a variable, N is the number of denture images in sequence Map2, and PAT is the gradient color difference ratio; GaryG(TC-i×time1) is the i-th gradient color difference interval. The calculation method of GaryG(TC-i×time1) is as follows: take the sequence closest to time TC-i×time1 in the reverse time order and satisfy the average value of all gray values ​​being less than or equal to |Gray(TC)-Gray(TC-time1)|. The acquisition time of the denture image in Map2 is T1, then GaryG(TC-i×time1) is the duration from time T1 to time TC-i×time1. Where Gray(TC-time1) is the average gray value of all pixels in the denture image at time TC-time1; Where Mean(Gray1,Gray2) is the average of Gray1 and Gray2; Starting from the current time TC, continue to irradiate the surface of the color-changing denture with ultraviolet light. If the average gray value of all pixels in the acquired denture image is less than or equal to GrayGap within the time tNext from TC to the color state conversion calculation time, then stop irradiating the surface of the color-changing denture with ultraviolet light to obtain the matched denture; otherwise, stop irradiating the surface of the color-changing denture with ultraviolet light at the time tNext to obtain the matched denture.

2. The method for preparing color-changing dentures according to claim 1, characterized in that, In S1, the crown image is obtained by taking pictures of the patient's crown using a dental camera, intraoral camera, CCD camera, or digital camera.

3. The method for preparing color-changing dentures according to claim 1, characterized in that, The method for preparing color-changing dentures includes: acquiring three-dimensional data of a plaster model or dental impression of the patient's oral cavity using an extraoral scanner; or, directly scanning the patient's oral cavity with an intraoral scanner to obtain three-dimensional data of the patient's oral cavity; designing a denture mold based on the three-dimensional data of the patient's oral cavity and transmitting it to a 3D printer for printing to obtain a printed denture mold; grinding the printed denture mold using a grinding machine according to the three-dimensional data of the patient's oral cavity to obtain a denture mold; and injecting denture material into the denture mold to produce color-changing dentures.

4. The method for preparing color-changing dentures according to claim 1, characterized in that, In S3, the method of matching the color of discolored dentures based on crown images to obtain well-matched dentures is replaced with: The surface of the discolored dentures was irradiated with ultraviolet light in the wavelength range of 150nm to 350nm; Using a crown image as a reference image, the reference image is segmented using a watershed algorithm or an edge detection operator to obtain multiple image regions. In each image region of the reference image, the grayscale images of two adjacent teeth are marked as two adjacent tooth images. The average grayscale values ​​of all pixels in the two adjacent tooth images are Gray1 and Gray2, respectively, and the absolute value of the difference between Gray1 and Gray2 is denoted as GrayGap. The CCD camera acquires images of the discolored dentures in real time as the target images, with the moment when ultraviolet light irradiation of the surface of the discolored dentures begins to be T0; the time interval for the CCD camera to acquire the target images is time1. The target image is segmented into multiple image regions using the watershed algorithm or edge detection operator. The grayscale image of the discolored denture is marked in each image region of the target image as the denture image. Alternatively, the grayscale image of the discolored denture in the target image is identified by the YOLO object detection algorithm as the denture image. Starting from time T0, real-time acquisition of denture images is performed. If the average gray value of all pixels in the denture image at the current time TC, Gray(TC), satisfies the condition: |Gray(TC)-Mean(Gray1,Gray2)|≤GrayGap, then the ultraviolet light irradiation on the surface of the discolored denture is stopped, thereby obtaining the matched denture. Here, Mean(Gray1,Gray2) is the average value of Gray1 and Gray2.

5. The method for preparing color-changing dentures according to claim 4, characterized in that, The surface of the discolored denture is irradiated with ultraviolet light in the wavelength range of 150nm to 350nm by any one of the following: high-intensity ultraviolet high-pressure mercury lamp, high-intensity metal halide lamp, exposure lamp, capillary ultra-high-pressure mercury lamp, light cleaning lamp, optical disc lamp, ultraviolet iron lamp, sterilization lamp, short-arc xenon lamp, or excimer discharge lamp.

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