Computer color matching method for 3D printing dental polyetheretherketone composites

Abstract

The present invention discloses a computer color matching method for 3D printing dental polyetheretherketone composite materials, which relates to the field of dentistry, including raw materials of PEEK, TiO2, zirconium praseodymium yellow, zirconium iron red and zirconium vanadium blue, adding TiO2 to PEEK to improve the base color, and on this basis, adding different concentrations and different types of zirconium-based colorants to make test pieces, and obtaining the corresponding change relationship between the reflectance spectrum rate, the chromaticity value and the added colorant. Taking the IvoclarShade Guide colorimetric plate as the target color, the reflectance spectrum and the chromaticity value of each colorimetric plate are tested, and the three-stimulus value color matching method and the full-spectrum color matching method are used for computer color matching to obtain formula data. The present invention uses intelligent color matching means of three-stimulus value color matching and full-spectrum theoretical color matching to establish a color matching model for 3D printing dental PEEK composite materials, so that PEEK colors are more diverse, the color matching is more accurate, and the use is more convenient; it avoids the most common mechanical complication of PEEK restorations-the problem of veneer resin peeling, and avoids the problem of inaccurate color matching caused by relying on technician experience, and can accurately obtain a variety of colors.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of dentistry, and in particular to a computer color matching method for 3D printing dental polyetheretherketone composite materials. Background Art

[0002] The organic polymer material polyetheretherketone (PEEK) is a material with good mechanical properties, high temperature resistance, stable chemical properties, polishability, radiation transmission, and low plaque affinity. Its elastic modulus is between cortical bone and cancellous bone, and its tensile properties are similar to those of enamel and dentin. Due to its excellent biocompatibility and mechanical properties, polyetheretherketone is used in many fields of the oral cavity. However, due to its brown color and opacity, its poor aesthetic properties as an oral restoration material limit the wide application of PEEK and its composite materials in the field of dental restoration. At present, there are two main methods to improve its color. One is to use the finishing resin to cover the color, but due to the low surface energy of PEEK, it is difficult to bond with the material and the finishing resin is easy to peel off. The other is to add nanofillers to PEEK for blending and color change. However, how to obtain simulated restoration effects is still a research difficulty. The manufacturing process of traditional polymer materials is mainly injection molding and CNC milling, which has complicated procedures, long processing cycles, serious waste, and high costs. The mold needs to be remade when personalized design is suitable for the production of large quantities of test pieces. With the advancement of rapid additive technology, personalized artificial parts have gradually become a development trend. Through 3D printing technology, personalized prostheses can be customized for patients, with high material utilization, which can greatly improve the adaptability of prostheses. The fused deposition modeling (FDM) process is an important branch of 3D printing. It uses the adhesiveness of thermoplastic materials to heat the material to a molten state, extrude the semi-fluid hot melt material under the system command, and the viscous material quickly solidifies. Through the "bottom-up" layer-by-layer stacking method, precision parts are manufactured, and the application prospects are good. FDM is considered to be the best 3D printing technology for PEEK materials.

[0003] Inorganic pigments are heat-resistant, sun-resistant, and have strong hiding power. Zirconium-based pigments with high-temperature stability are typical representatives. Zirconium-based pigments are often used in the color matching of dental ceramic materials, and can be arbitrarily combined to produce a rich color system. Compared with manual color matching, computer color matching has the advantages of good guidance, convenient color matching, and high color matching accuracy. The reflectance spectrum curves of the color matching sample and the target color sample are measured by a color measuring instrument, and the color matching software calculates and gives the best pigment formula. Many studies have successfully applied zirconium-based pigments to computer color matching. The reflectance spectrum characteristics of PEEK composites are the basis of computer color matching. By mathematically correlating them with the target color, the color matching scheme of tooth-colored PEEK composites can be obtained, thereby improving the color properties of PEEK.

[0004] It has been reported that the color properties of PEEK can be changed by regulating the way of PEEK blending oxides. There are two main types of commercial PEEK on the domestic dental market. Bio-HPP (Bidan, Germany) is a PEEK-based ceramic-reinforced high-performance polymer material, which is added with 20wt% ZrO2 and Al2O3 and manufactured by high-temperature die casting; the domestic BioPAEK (Jilin Province Dentech Dental Co., Ltd.) series of digital milling discs obtain three color number discs of W, P, and Y by adding different contents of TiO2 and Fe2O3, and the colors available are limited. Lu Wei's team adopted the pigment oxide blending modification strategy of "first calibrating the base color, then adjusting the tooth color", adding one of TiO2, ZrO2, and Al2O3 to PEEK with a mass percentage of 2%-20%, and printing tooth color shade plates; on this basis, 0.2%-1.2% Fe2O3 was added to obtain a gingival color shade plate, but the relationship between the oxide ratio, type and color changes is still unclear.

[0005] In summary, the problems existing in the prior art are: the colors of polyetheretherketone composites are limited, and the relationship between the proportion and type of added oxides and the color changes is still unclear, and it is impossible to accurately obtain a color close to that of natural teeth. Summary of the invention

[0006] Based on this, the object of the present invention is to provide a computer color matching method for 3D printing dental polyetheretherketone composite materials to solve the technical problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A computer color matching method for 3D printing dental polyetheretherketone composite materials comprises the following steps:

[0009] Step 1: Weighing: Weigh the raw material quantity of each powder according to the ratio, and the weighing accuracy of the raw material is controlled within 0.001g;

[0010] Step 2, drying: Dry the weighed powders separately one by one, put them into a tray with aluminum foil and cover it, the temperature is 120°, and the drying time is 4 hours;

[0011] Step 3, mixing: put the powder into a mixer for mixing, the temperature is 120°, the mixing time is 12 hours, and the mixture is dried for 6 hours;

[0012] Step 4: Extrusion: The dried raw materials are placed in a screw machine. The raw materials undergo seven processes in the extrusion process, including drying, feeding, extrusion, cooling, shearing, stretching and winding. The screw rod pushes the die head to extrude a viscous film. After heating, the longitudinal strength of the flat wire is increased under the tensile traction force, and finally the wire is drawn and wound;

[0013] Step 5: Print PEEK and its composite material specimens, polish them with 600#, 1000#, 1500#, 2000# and 3000# water sandpaper, and then clean and dry them;

[0014] The raw materials are PEEK, TiO2, zirconium praseodymium yellow, zirconium iron red and zirconium vanadium blue;

[0015] The PEEK-TiO2 is prepared by adding TiO2 to PEEK to improve the base color. On this basis, different concentrations and types of zirconium-based colorants are added to prepare test pieces to obtain the corresponding change relationship between the reflectance spectrum, the chromaticity value and the different colorants. The Ivoclar Shade Guide colorimetric plate is used as the target color, the reflectance spectrum and chromaticity value of each colorimetric plate are tested, and the three-stimulus color matching method and the full-spectrum color matching method are used for computer color matching to obtain the formula data.

[0016] Specifically, in the step 2, the mixer is a V-shaped mixer.

[0017] In summary, the present invention mainly has the following beneficial effects:

[0018] (1) The present invention uses intelligent color matching methods of tristimulus value color matching and full spectrum theoretical color matching to establish a color matching model for 3D printed dental PEEK composites, making PEEK colors more diverse, color matching more accurate, and more convenient to use;

[0019] (2) Analyze the variation of the amount of pigment in the PEEK composite from the reflectance spectrum and color difference value, establish a color database, and make the color matching system intelligent and predictive;

[0020] (3) It can directly provide the pigment formula data of each color in the dental shade guide, thereby obtaining PEEK composites of various colors, avoiding the most common mechanical complication of PEEK restorations - resin stripping, and avoiding the problem of inaccurate color matching due to reliance on technician experience. Multiple colors can be accurately obtained through computer color matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of the steps of the present invention;

[0022] Figure 2 A color matching database chart of the tristimulus color matching method of the present invention;

[0023] Figure 3 A color matching database chart of the full spectrum color matching method of the present invention; DETAILED DESCRIPTION

[0024] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0025] The following describes an embodiment of the present invention based on its overall structure.

[0026] Example

[0027] Please refer to the attached Figure 1-3 As shown, the computer color matching method for 3D printing dental polyetheretherketone composite material is characterized by comprising the following steps:

[0028] Step 1: Weighing: Weigh the raw material quantity of each powder according to the ratio, and the weighing accuracy of the raw material is controlled within 0.001g;

[0029] Step 2, drying: Dry the weighed powders separately one by one, put them into a tray with aluminum foil and cover it, the temperature is 120°, and the drying time is 4 hours;

[0030] Step 3, mixing: put the powder into the mixer for mixing. The mixer is a V-shaped mixer. The V-shaped mixer has a unique structure, uniform mixing, high efficiency, and no material accumulation. Through reciprocating motion, the material is turned over for fluidity to achieve the purpose of uniform mixing. The temperature is 120°, the powder mixing time is 12 hours, and the mixed material is dried for 6 hours;

[0031] Step 4: Extrusion: The dried raw materials are placed in a screw machine. The raw materials undergo seven processes in the extrusion process, including drying, feeding, extrusion, cooling, shearing, stretching and winding. The screw rod pushes the die head to extrude a viscous film. After heating, the longitudinal strength of the flat wire is increased under the tensile traction force, and finally the wire is drawn and wound;

[0032] Step 5: Print PEEK and its composite material specimens, polish them with 600#, 1000#, 1500#, 2000# and 3000# water sandpaper, and then clean and dry them.

[0033] The raw materials are PEEK, TiO2, zirconium praseodymium yellow, zirconium iron red and zirconium vanadium blue. TiO2 is added to PEEK to improve the base color. On this basis, zirconium-based colorants of different concentrations and types are added to make test pieces. The corresponding change relationship between the reflectance spectrum and chromaticity value and different colorants is obtained. The Ivoclar Shade Guide colorimetric plate is used as the target color, the reflectance spectrum and chromaticity value of each colorimetric plate are tested, and the three-stimulus color matching method and the full-spectrum color matching method are used for computer color matching to obtain the formula data.

[0034] The present invention of the present application utilizes intelligent color matching methods of tristimulus value color matching and full spectrum theoretical color matching to establish a color matching model for 3D printing dental PEEK composites, making PEEK colors more diverse, color matching more accurate, and more convenient to use; analyzing the changing rules of the amount of colorant in the PEEK composite from the reflectance spectrum and the color difference value, establishing a color database, and making the color matching system intelligently predictable; directly providing the colorant formula data of each color in the dental shade plate, thereby obtaining PEEK composites of various colors, avoiding the problem of resin stripping, which is currently the most common mechanical complication of PEEK restorations, and avoiding the problem of inaccurate color matching due to reliance on technician experience, and accurately obtaining a variety of colors through computer color matching.

[0035] Example 1

[0036] A computer color matching method for 3D printing dental polyetheretherketone composite materials, characterized in that it comprises the following steps:

[0037] Step 1: Weighing: Weigh the raw material quantity of each powder according to the ratio, and the weighing accuracy of the raw material is controlled within 0.001g;

[0038] Step 2, drying: Dry the weighed powders separately one by one, put them into a tray with aluminum foil and cover it, the temperature is 120°, and the drying time is 4 hours;

[0039] Step 3, mixing: put the powder into a mixer for mixing. The mixer is a V-shaped mixer. The temperature is 120°, the mixing time is 12 hours, and the mixture is dried for 6 hours.

[0040] Step 4: Extrusion: The dried raw materials are placed in a screw machine. The raw materials undergo seven processes in the extrusion process, including drying, feeding, extrusion, cooling, shearing, stretching and winding. The screw rod pushes the die head to extrude a viscous film. After heating, the longitudinal strength of the flat wire is increased under the tensile traction force, and finally the wire is drawn and wound;

[0041] Step 5: Print PEEK and its composite material specimens, polish them with 600#, 1000#, 1500#, 2000# and 3000# water sandpaper, and then clean and dry them.

[0042] See below Figure 3 Color matching database based on stimulus value color matching method.

[0043] Tristimulus color matching database

[0044]

[0045]

[0046] The types and proportions of the components and mixtures of the PEEK composite material are all prepared according to the data provided in the above table of this example.

[0047] The PEEK composite material components provided in this example are:

[0048] Y1 group: 20wt% TiO2-0.1wt% zirconium praseodymium yellow-PEEK; Y2 group: 20wt% TiO2-0.5wt% zirconium praseodymium yellow-PEEK; Y3 group: 20wt% TiO2-1wt% zirconium praseodymium yellow-PEEK

[0049] R1 group: 20wt% TiO2-0.1wt% ferrozirconium red-PEEK; R2 group: 20wt% TiO2-0.5wt% ferrozirconium red-PEEK; R3 group: 20wt% TiO2-1wt% ferrozirconium red-PEEK

[0050] Group B1: 20wt% TiO2-0.1wt% zirconium vanadium blue-PEEK; Group B2: 20wt% TiO2-0.5wt% zirconium vanadium blue-PEEK; Group B3: 20wt% TiO2-1wt% zirconium vanadium blue-PEEK

[0051] Chromaticity measurement: L*, a*, and b* values ​​were measured using a Datacolor spectrophotometer under D65 light source. A white plate was measured to calibrate the instrument before measurement. Each group was measured three times. Three concentration points in the center of each specimen were randomly selected for measurement, and the average value was taken as the final result. Optical geometry conditions: d / 8 degree integrating sphere, area: ultra-small aperture (USAV).

[0052] Reflection spectrum acquisition: Use Datacolor spectrophotometer to measure the reflection spectrum. The measurement conditions are the same as before. Obtain the reflectance data of three monochromatic gradient concentration samples in the spectral range of 400-700nm, with an interval of 10nm. When measuring the sample, please note: a relatively smooth point in the center of the specimen should be selected, and the specimen should completely cover the measurement hole of the spectrometer.

[0053] The Ivoclar Shade Guide colorimetric plate was used as the target color to test the reflectance spectrum and chromaticity value of each colorimetric film.

[0054] The Kubelka-Munk theory is a theory of absorption and scattering of light, and is usually used to predict the color of opaque or translucent objects.

[0055] The basic formula of KM theory is as follows:

[0056]

[0057] When incident light hits an object, part of the light is scattered, another part is absorbed, and another part is transmitted. Where ρ is the reflectivity, ρg is the background reflectivity, α=1+(K / S); b=(α2-1)1 / 2, coth(bSX) is the hyperbolic cotangent function, K is the light absorption rate per unit thickness, and S is the light scattering rate per unit thickness.

[0058] For opaque media, when the S value or the thickness of the specimen increases to infinity, the simplified form of the equation is obtained:

[0059] ρ ∞ =1+(K / S)-[(K / S) 2 +2(K / S)] 1 / 2 (2)

[0060] at this time

[0061] Formula (3) is the opaque sample equation, where ρ∞ is the scattering coefficient or the reflectivity when the medium thickness increases to infinity, and the K / S value appears in the form of a ratio. The present invention improves the accuracy of color matching by establishing a computer color matching method suitable for low translucency dental materials, and promotes the application of the material in the field of restoration.

[0062] Three stimulus value color matching: Apply KM theory to three stimulus value color matching. The algorithm is based on KM theory. According to the obtained single sample concentration gradient spectral reflectance and the spectral reflectance value of the target sample, the K and S ratios of the monochrome sample and the target sample are calculated respectively. The K / S values ​​of the two are matched through the three stimulus value matrix, and the initial predicted formula of each colorant is calculated using the colorant concentration relationship and the K / S value. Finally, the colorant formula closest to the target is selected. The corresponding color matching formula of each colorimetric film is obtained, and the color difference value ΔE between the color matching database obtained by the three stimulus value color matching method and the computer software system is calculated.

[0063] Example 2

[0064] Full spectrum color matching database

[0065]

[0066]

[0067] Full spectrum color matching theory color matching: Use Datacolor color matching software, the algorithm is based on KM theory.

[0068] The basic formula of KM theory is as follows:

[0069]

[0070] When incident light hits an object, part of the light is scattered, another part is absorbed, and another part is transmitted. Where ρ is the reflectivity, ρg is the background reflectivity, α=1+(K / S); b=(α2-1)1 / 2, coth(bSX) is the hyperbolic cotangent function, K is the light absorption rate per unit thickness, and S is the light scattering rate per unit thickness.

[0071] For opaque media, when the S value or the thickness of the specimen increases to infinity, the simplified form of the equation is obtained:

[0072] ρ ∞ =1+(K / S)-[(K / S) 2 +2(K / S)] 1 / 2 (2)

[0073] at this time

[0074] Formula (3) is the equation for an opaque sample, where ρ∞ is the scattering coefficient or the reflectivity when the medium thickness increases to infinity, and the K / S value appears in the form of a ratio.

[0075] Referring to the McGinnis color matching algorithm, the K / S value is obtained by the spectral reflectance values ​​of the three monochromatic concentrations of PEEK, the K / S value (Φ value) of the corresponding concentration unit is calculated, the Φ value of each concentration is obtained by the Lagrange formula, and the K / S value of the color matching sample matching the target sample is calculated. The average value of the difference between the two is calculated, and the optimal value is taken as the minimum square value. The optimal predicted formula value of each colorant is approximated by the least squares method, and the color difference value ΔE between the color matching database and the computer software system obtained by the full spectrum color matching method is calculated.

[0076] It should be noted that, in addition to the above implementation examples, the present invention has other implementation modes, which will be subject to corresponding changes and modifications, all of which fall within the protection scope required by the present invention.

[0077] The working principle of the present invention is:

[0078] The following steps are involved:

[0079] Step 1: Weighing: Weigh the raw material quantity of each powder according to the ratio, and the weighing accuracy of the raw material is controlled within 0.001g;

[0080] Step 2, drying: Dry the weighed powders separately one by one, put them into a tray with aluminum foil and cover it, the temperature is 120°, and the drying time is 4 hours;

[0081] Step 3, mixing: put the powder into a mixer for mixing. The mixer is a V-shaped mixer. The temperature is 120°, the mixing time is 12 hours, and the mixture is dried for 6 hours.

[0082] Step 4: Extrusion: The dried raw materials are placed in a screw machine. The raw materials undergo seven processes in the extrusion process, including drying, feeding, extrusion, cooling, shearing, stretching and winding. The screw rod pushes the die head to extrude a viscous film. After heating, the longitudinal strength of the flat wire is increased under the tensile traction force, and finally the wire is drawn and wound;

[0083] Step 5: Print PEEK and its composite material specimens, polish them with 600#, 1000#, 1500#, 2000# and 3000# water sandpaper, and then clean and dry them.

[0084] The raw materials are PEEK, TiO2, zirconium praseodymium yellow, zirconium iron red and zirconium vanadium blue. TiO2 is added to PEEK to improve the base color. On this basis, zirconium-based colorants of different concentrations and types are added to make test pieces. The corresponding change relationship between the reflectance spectrum and chromaticity value and different colorants is obtained. The Ivoclar Shade Guide colorimetric plate is used as the target color, the reflectance spectrum and chromaticity value are tested, and the three-stimulus color matching method and the full-spectrum color matching method are used for computer color matching to obtain the formula data.

[0085] The present invention of the present application utilizes intelligent color matching methods of tristimulus value color matching and full spectrum theoretical color matching to establish a color matching model for 3D printing dental PEEK composites, making PEEK colors more diverse, color matching more accurate, and more convenient to use; analyzing the changing rules of the amount of colorant in the PEEK composite from the reflectance spectrum and the color difference value, establishing a color database, and making the color matching system intelligently predictable; directly providing the colorant formula data of each color in the dental shade plate, thereby obtaining PEEK composites of various colors, avoiding the problem of resin stripping, which is currently the most common mechanical complication of PEEK restorations, and avoiding the problem of inaccurate color matching due to reliance on technician experience, and accurately obtaining a variety of colors through computer color matching.

[0086] Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiments without creative contributions as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A computer color matching method for 3D printing dental polyetheretherketone composite materials, characterized in that: The following steps are involved: Step 1: Weighing: Weigh the raw material quantity of each powder according to the ratio, and the weighing accuracy of the raw material should be controlled within 0.001g; Step 2, drying: Dry the weighed powders separately one by one, put them into a tray with aluminum foil and cover them, the temperature is 120°, and the drying time is 4 hours; Step 3, mixing: put the powder into a mixer for mixing at a temperature of 120°, mixing time of 12 hours, and drying the mixture for 6 hours; Step 4: Extrusion: The dried raw materials are placed in a screw machine. The raw materials undergo seven processes in the extrusion process, including drying, feeding, extrusion, cooling, shearing, stretching and winding. The screw rod pushes the die head to extrude a viscous film. After heating, the longitudinal strength of the flat wire is increased under the tensile traction force, and finally the wire is drawn and wound; Step 5: Print PEEK and its composite material specimens, polish them with 600#, 1000#, 1500#, 2000# and 3000# water sandpaper, and then clean and dry them; The raw materials are PEEK, TiO2, zirconium praseodymium yellow, zirconium iron red and zirconium vanadium blue; TiO2 was added to PEEK to improve the base color. On this basis, different concentrations and types of zirconium-based pigments were added to make test pieces. The corresponding relationship between the reflectance spectrum, chromaticity value and different pigments was obtained. The reflectance spectrum and chromaticity value of each colorimetric plate were tested using the Ivoclar Shade Guide colorimetric plate as the target color. The three-stimulus color matching method and the full-spectrum color matching method were used for computer color matching to obtain the formula data. In the step 3, the mixer is a V-shaped mixer.

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