Three-dimensional printing method and system for a graded color dental restoration

Abstract

The present application relates to the technical field of tooth restoration, in particular to a three-dimensional printing method and system for a gradient color tooth restoration body. The present application divides a restoration body model of a target tooth to be restored into a plurality of tooth restoration layers, determines a target color of each tooth restoration layer by taking tooth color change data of healthy adjacent teeth as a reference, and then sorts the target colors of all tooth restoration layers according to a rule from light to dark as a printing order. Finally, the target color is taken as a printing target, and based on a pre-set color matching supply strategy and an exposure control strategy, each tooth restoration layer of the restoration body model is sequentially three-dimensionally printed according to the printing order to obtain a gradient color tooth restoration body of the target tooth, so that a gradient color tooth restoration body with a smaller color difference from healthy adjacent teeth is obtained, and the restoration effect is better.

Description

Technical Field

[0001] This invention relates to the field of dental restoration technology, specifically to a method and system for 3D printing gradient-colored dental restorations. Background Technology

[0002] In the field of dental restoration, the color accuracy of dental restorations (such as crowns and veneers) is one of the key factors affecting the restoration outcome. The color of natural teeth is not uniform; it typically deepens gradually along the crown height from the incisal edge to the neck.

[0003] Currently, the use of 3D printing technology (such as 3D printing technologies based on the principle of light curing, such as DLP and LCD) to fabricate dental restorations is gradually being applied in clinical practice. Existing 3D printing systems are usually equipped with only a single color of light-cured resin material, and the printing process is a continuous homogeneous stacking, which cannot print dental restorations that conform to the color gradation of natural teeth. When worn in the patient's mouth, there is a large color difference with other healthy teeth, resulting in poor restorative effects. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for 3D printing gradient-colored tooth restorations. The restoration model of the target tooth to be restored is divided into multiple tooth restoration layers. The target color of each tooth restoration layer is determined by using the color change data of healthy adjacent teeth as a reference. Then, each tooth restoration layer is printed sequentially to obtain a gradient-colored tooth restoration with a small color difference from the healthy adjacent teeth, resulting in better restoration effect.

[0005] In a first aspect, the present invention provides a method for three-dimensional printing of gradient-colored dental restorations, comprising:

[0006] For the target tooth to be restored, obtain data on the color change of the tooth body along the crown height direction on the labial surface of the healthy adjacent tooth;

[0007] The pre-constructed model of the target tooth restoration is sliced ​​to obtain multiple tooth restoration layers;

[0008] Based on the color change data of the labial surface of healthy adjacent teeth, the target color of each restorative layer of the restoration model is determined;

[0009] The target colors for all dental restoration layers are sorted from lightest to darkest as the printing order;

[0010] Using the target color as the printing target, and based on the pre-set color matching and exposure control strategies, the various tooth restoration layers of the restoration model are sequentially 3D printed according to the printing order to obtain a gradient-colored tooth restoration of the target tooth.

[0011] Optionally, the tooth color change data includes a tooth color change function that characterizes the mapping relationship between tooth height and tooth color.

[0012] Optionally, slicing to obtain multiple dental restoration layers includes:

[0013] Equally spaced sections were used to obtain multiple dental restoration layers of the same thickness.

[0014] Optionally, by referring to the color change data of healthy adjacent teeth, the target color for each restorative layer of the restoration model is determined, including:

[0015] For each tooth restoration layer, the reference tooth height on the labial surface of the healthy adjacent tooth corresponding to the current tooth restoration layer is determined based on the relative height position of the current tooth restoration layer between the incisal edge of the crown and the neck of the tooth in the restoration model.

[0016] The tooth color corresponding to the reference tooth height in the tooth color change data is used as the target color of the current tooth restoration layer.

[0017] Optionally, tooth color includes a lightness value;

[0018] The target colors for all dental restoration layers are sorted from lightest to darkest as the printing order, including:

[0019] Sort all target colors of the dental restoration layers in descending order of lightness value as the printing order.

[0020] Optionally, based on a pre-set color matching and material supply strategy and an exposure control strategy, the three-dimensional printing of each tooth restoration layer of the restoration model is performed sequentially according to the printing order, including:

[0021] Before printing each dental restoration layer, the target color of that dental restoration layer is used as the color matching target, and the amount of color matching supplement for each color matching resin is determined according to the pre-set color matching supply strategy.

[0022] After the printing resin in the printing tank is replenished according to the specified color matching amount, the desired radial saturation distribution is used as the curing target. The exposure parameters for 3D printing are determined according to the preset exposure control strategy, and the tooth restoration layer is 3D printed based on the exposure parameters.

[0023] Optionally, determining the amount of color replenishment for each color resin according to a pre-set color matching supply strategy includes:

[0024] For the first printed dental restoration layer:

[0025] Using the target color of the dental restoration layer as the color matching target, determine the amount of color matching supplement for each color matching resin required for printing the current dental restoration layer;

[0026] For each subsequent printed layer of dental restoration:

[0027] Before printing the current dental restoration layer, the target color of the current dental restoration layer is used as the color matching target. Based on the resin mixture color and total volume of the remaining printing resin in the printing tank after the last printing, the amount of resin supplement required for each color matching layer is determined.

[0028] Optionally, when determining the amount of each color matching resin required for printing the current dental restoration layer, a color matching supplement constraint is set for the total color matching supplement amount, wherein the total color matching supplement amount is the sum of the color matching supplement amounts of each color matching resin;

[0029] The color matching replenishment constraint includes: the volume ratio of the total replenishment amount to the total volume of printing resin remaining in the printing tank after the last printing is less than a preset volume ratio threshold.

[0030] Optionally, the total volume of remaining printing resin in the printing cavity is updated after each dental restoration layer is printed. The updating methods include:

[0031] For the first printed dental restoration layer:

[0032] The total volume of printing resin remaining in the printing groove after the current dental restoration layer printing is completed is determined based on the difference between the total amount of color replenishment and the amount of resin consumed in this printing.

[0033] For each subsequent printed layer of dental restoration:

[0034] Based on the total volume of printing resin remaining in the printing tank after the previous printing, the total volume of printing resin remaining in the printing tank after the current printing is determined according to the difference between the total amount of color replenishment and the amount of resin consumed in this printing.

[0035] The total color replenishment amount is the sum of the color replenishment amounts of each color resin.

[0036] Optionally, the resin mixture color of the remaining printing resin in the printing chamber is updated after each dental restoration layer is printed. The updating methods include:

[0037] The target color of this print will be used as the resin mixing color of the remaining printing resin in the print tank after the print is completed.

[0038] Optionally, the tooth color includes red-green axis coordinate values, yellow-blue axis coordinate values, and lightness values, and the color matching resin includes a first resin, a second resin, a third resin, and a fourth resin;

[0039] By increasing the volume ratio of the first resin in the printing resin within the printing tank, the red-green axis coordinate values ​​of the resin mixture color within the printing tank can be shifted towards the red direction.

[0040] By increasing the volume ratio of the second resin in the printing resin within the printing tank, the yellow-blue axis coordinate value of the resin mixture color within the printing tank can be shifted towards the yellow direction.

[0041] By increasing the volume ratio of the third resin in the printing tank and decreasing the volume ratio of the fourth resin in the printing tank, the brightness value of the mixed color of the printing resin in the printing tank can be increased.

[0042] Optionally, with the desired radial saturation distribution as the curing target, the exposure parameters for 3D printing are determined according to a pre-set exposure control strategy, including:

[0043] The cross-sectional profile of the center height of the dental restoration layer is obtained using a cutting plane orthogonal to the crown height direction;

[0044] The desired radial saturation distribution is determined based on the cross-sectional profile, and the desired radial saturation distribution characterizes the correspondence between radial position points on the cross-sectional profile and the desired saturation.

[0045] Based on a pre-built correlation table between saturation and exposure energy, the required exposure energy for each radial position point on the cross-sectional profile is determined according to the desired radial saturation distribution.

[0046] The exposure parameters for 3D printing are determined based on the required exposure energy at each radial position point.

[0047] In a second aspect, the present invention provides a three-dimensional printing system for gradient-colored dental restorations, comprising:

[0048] The identification module is used to acquire data on the color change of the labial surface of healthy adjacent teeth along the crown height direction for the target tooth to be repaired;

[0049] The slicing module is used to slice a pre-built model of the target tooth restoration to obtain multiple tooth restoration layers;

[0050] The color determination module is used to determine the target color of each tooth restoration layer in the restoration model by referring to the tooth color change data of the labial side of healthy adjacent teeth.

[0051] The sequence determination module is used to sort the target colors of all dental restoration layers according to a rule from light to dark as the printing order;

[0052] The printing module is used to print each tooth restoration layer of the restoration model in three dimensions according to the printing order, based on the target color and a pre-set color matching feeding strategy and exposure control strategy, to obtain a gradient-colored tooth restoration of the target tooth.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] This invention, for the target tooth to be restored, first obtains the tooth color change data along the crown height direction of the labial surface of the healthy adjacent tooth; slices the pre-constructed restoration model of the target tooth to obtain multiple tooth restoration layers; and determines the target color of each tooth restoration layer of the restoration model by referring to the tooth color change data along the crown height direction of the labial surface of the healthy adjacent tooth; this invention divides the restoration model of the target tooth into multiple tooth restoration layers, and uses the tooth color change data along the crown height direction of the labial surface of the healthy adjacent tooth as a reference to determine the target color of each tooth restoration layer. Subsequently, printing according to the target color can produce a gradient tooth restoration with a small color difference from the healthy adjacent tooth. Since the printing resin in the printing chamber accumulates layer by layer and gradually changes from light to dark, this invention sorts the target colors of all dental restoration layers according to a rule from light to dark as the printing order. This facilitates precise control of the target color of the dental restoration layer through the accumulation and color matching of the printing resin in the printing chamber. Finally, using the target color as the printing target, based on a pre-set color matching and exposure control strategy, each dental restoration layer of the restoration model is 3D printed sequentially according to the printing order to obtain a gradient-colored dental restoration of the target tooth. In specific applications, the solution of this invention can be used for dental crown restorations (including single crowns or bridge crowns) and dentures inlaid on denture bases. The dental restorations printed by this method have a tooth color close to that of healthy adjacent teeth and are close to the sensory appearance of real teeth when installed in the oral cavity. Therefore, it effectively improves the dental restoration effect. Attached Figure Description

[0055] Figure 1 This is a flowchart illustrating the three-dimensional printing method for gradient-colored dental restorations provided in an embodiment of the present invention.

[0056] Figure 2 This is a schematic cross-section of a dental restoration according to an embodiment of the present invention.

[0057] Figure 3 This is a schematic diagram of the exposure control of one of the dental restoration layers in an embodiment of the present invention.

[0058] Figure 4 This is a schematic diagram of the modules of the gradient-colored dental restoration 3D printing system provided in an embodiment of the present invention. Detailed Implementation

[0059] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0060] Combination Figure 1 This embodiment provides a method for 3D printing gradient-colored dental restorations, which includes:

[0061] Step S1: For the target tooth to be repaired, obtain the tooth color change data along the crown height direction on the labial surface of the healthy adjacent tooth.

[0062] This embodiment uses an oral impression instrument to collect three-dimensional morphological data of healthy adjacent teeth, and then uses a colorimeter to collect the tooth color at various heights along the crown height direction on the labial surface of the healthy adjacent teeth. Based on the three-dimensional morphological data of the healthy adjacent teeth, the tooth color variation data can be obtained by arranging the tooth color on the labial surface of the healthy adjacent teeth along the crown height direction. In this embodiment, the tooth color is recorded using the L parameter, a parameter, and b parameter in the CIE Lab color space. The L parameter (Lightness) is the brightness value, representing the lightness of the tooth color, typically ranging from 0 (pure black) to 100 (pure white), with higher values ​​indicating greater brightness. The a parameter (Red-Green Axis) is the red-green axis coordinate value, representing the change of tooth color in the "red-green" direction, with positive values ​​(+a) indicating a tendency towards red and negative values ​​(-a) indicating a tendency towards green. The b parameter (Yellow-Blue Axis) is the yellow-blue axis coordinate value, representing the change of tooth color in the "yellow-blue" direction, with positive values ​​(+b) indicating a tendency towards yellow and negative values ​​(-b) indicating a tendency towards blue.

[0063] The tooth color change data includes a tooth color change function that characterizes the mapping relationship between tooth height and tooth color. The construction steps of the tooth color change function include: sampling tooth colors at different tooth heights z (z is a normalized value based on the incisal edge and cervical position of the crown; after normalization, 0 represents the incisal edge and 1 represents the cervical position), and fitting the tooth color change function of the healthy adjacent tooth. The tooth color change function includes a lightness change function L(z), a red-green axis change function a(z), and a yellow-blue axis change function b(z). The tooth color change function can be obtained through linear interpolation, spline interpolation, and other existing methods with similar functions. The lightness change function L(z), the red-green axis change function a(z), and the yellow-blue axis change function b(z) can describe the gradual color change trend of the healthy adjacent tooth from the incisal edge to the cervical position.

[0064] Step S2, Combining Figure 2The pre-constructed prosthesis model of the target tooth is sliced ​​to obtain multiple tooth restoration layers. The prosthesis model of the target tooth is constructed based on the three-dimensional morphological data of the target tooth collected by the dental impression instrument. In this embodiment, equally spaced slices are used, and the thickness of the multiple tooth restoration layers is consistent.

[0065] Step S3: Refer to the color change data of the labial side of healthy adjacent teeth to determine the target color of each tooth restoration layer in the restoration model;

[0066] For each dental restoration layer, based on the relative height of the current dental restoration layer between the incisal edge and cervical position of the crown in the restoration model, a reference tooth height corresponding to the current dental restoration layer on the labial surface of the healthy adjacent tooth is determined. Specifically, in this embodiment, the normalized value of the center height of the current dental restoration layer is determined based on the incisal edge and cervical position of the crown in the restoration model. Based on this normalized value, a reference tooth height corresponding to the current dental restoration layer on the labial surface of the healthy adjacent tooth is determined. The tooth color corresponding to the reference tooth height in the tooth color change data is used as the target color of the current dental restoration layer. As an example, the target color of the i-th dental restoration layer is {L}. i a i b i}={L(z i ), a(z i ), b(z) i )}, where L i a represents the lightness value of the target color for the i-th dental restoration layer. i b represents the red-green axis coordinate value of the target color of the i-th tooth restoration layer. i The z-axis coordinates represent the target color of the i-th dental restoration layer. i This represents the reference tooth height on the labial surface of the healthy adjacent tooth corresponding to the i-th restoration layer. i Substituting the lightness variation function, red-green axis variation function, and yellow-blue axis variation function into the formula yields the target color of the i-th tooth restoration layer.

[0067] Step S4: Sort the target colors of all dental restoration layers from light to dark as the printing order.

[0068] It is worth noting that the target color of the dental restoration layer closer to the incisal edge of the crown is usually brighter than that on the cervical side. In this embodiment, to accommodate the layer-by-layer accumulation of printing resin within the printing chamber, each dental restoration layer is printed in order of "target color from light to dark." This ensures that the actual color of the printing resin within the printing chamber gradually changes from light to dark during the printing process, facilitating precise control through cumulative color adjustment. This embodiment uses lightness value as the basis, sorting the target colors of all dental restoration layers in descending order of lightness value as the printing order.

[0069] Step S5: Using the target color as the printing target, based on the pre-set color matching material supply strategy and exposure control strategy, the three-dimensional printing of each tooth restoration layer of the restoration model is performed in sequence according to the printing order to obtain the gradient color tooth restoration of the target tooth.

[0070] Step S5 specifically includes:

[0071] Step S51: Before printing each dental restoration layer, the target color of the dental restoration layer is used as the color matching target, and the amount of color matching resin supplementation for each color matching layer is determined according to the pre-set color matching material supply strategy.

[0072] In this embodiment, for the first printed dental restoration layer (the first dental restoration layer), the target color {L1, a1, b1} of this dental restoration layer is used as the color matching target, and the color matching supplement amount of each color matching resin is determined; after the first printed dental restoration layer is completed, the total color matching supplement amount ΔV of this printing is obtained. feed(1) Resin consumption V cure(1) The total color replenishment amount is the sum of the color replenishment amounts of each color-matching resin; based on the total color replenishment amount ΔV feed(1) Resin consumption V cure(1) The difference determines the total volume V of the remaining printing resin in the printing groove after the printing of the first tooth restoration layer is completed. res(1) The target color {L1, a1, b1} of this printing is used as the resin mixing color of the remaining printing resin in the printing tank after the printing is completed.

[0073] Because each printing of a dental restoration layer only cures a portion of the resin in the printing chamber, leaving a large amount of resin residue, this embodiment, for each subsequent dental restoration layer, before the printing of the current dental restoration layer begins, uses the target color of the current dental restoration layer as the color matching target, and determines the amount of resin supplementation required for each color matching of the current dental restoration layer printing based on the resin mixture color and total volume of the remaining printing resin in the printing chamber after the previous printing.

[0074] The resin mixture color and total volume of the remaining printing resin in the printing chamber are updated after each tooth restoration layer is printed.

[0075] The method for updating the resin-mixed color includes: printing the target color {L} of the i-th dental restoration layer. i a i b i The color of the resin mixture remaining in the printing groove after the i-th tooth restoration layer has been printed.

[0076] The method for updating the total volume of remaining printing resin in the printing chamber includes: based on the total volume V of remaining printing resin in the printing chamber after the (i-1)th tooth restoration layer is printed. res(i-1) Based on the total supplementary amount ΔV of the color matching printed for the i-th tooth restoration layer feed(i) Resin consumption V cure(i) The difference is used to determine the total volume V of the remaining printing resin after the i-th tooth restoration layer is printed. res(i) The expression is: V res(i) =V res(i-1) -V cure(i) +ΔV feed(i)； Among them, V res(i) V represents the total volume of printing resin remaining after the i-th tooth restoration layer has been printed. res(i-1) V represents the total volume of printing resin remaining in the printing groove after the (i-1)th tooth restoration layer has been printed. cure(i) ΔV represents the amount of resin consumed during the printing of the i-th dental restoration layer. feed(i) This represents the total amount of color matching supplementation printed for the i-th tooth restoration layer. The total amount of color matching supplementation is the sum of the color matching supplementation amounts of each color matching resin.

[0077] In this embodiment, the tooth color is recorded using the lightness value (L parameter), red-green axis coordinate value (a parameter), and yellow-blue axis coordinate value (b parameter) in the CIE Lab color space. Increasing the volume ratio of the first resin in the printing tank shifts the red-green axis coordinate value of the mixed resin color towards red; increasing the volume ratio of the second resin shifts the yellow-blue axis coordinate value towards yellow; increasing the volume ratio of the third resin and decreasing the volume ratio of the fourth resin increases the lightness value of the mixed resin color. This embodiment uses four feeding components for each of the four color-matching resins. Each feeding component includes a resin tank, a metering pump or a stepper motor-driven syringe, and a delivery pipeline, which can quantitatively deliver the corresponding volume of resin to the printing tank according to the feeding program. The feeding procedure uses the layer number of the dental restoration layer as an index to record the amount of each color-matching resin required for each dental restoration layer. The amount of color-matching resin required for printing the first, second, third, and fourth resins for the i-th dental restoration layer is Δv, respectively. 1(i) Δv 2(i) Δv 3(i) Δv 4(i) The total amount of color matching supplement ΔV printed for the i-th tooth restoration layer. feed(i) =Δv 1(i) +Δv 2(i) +Δv 3(i) +Δv 4(i) Before printing each dental restoration layer, the feeding component feeds the required amount of resin according to the color matching requirements, so that the printing resin in the printing chamber can be adjusted to the target color required for the current dental restoration layer based on the remaining printing resin after the previous printing.

[0078] The process of determining the amount of color-matching resin to replenish each color according to a pre-set color-matching supply strategy is explained in detail. Taking the (i+1)th tooth restoration layer as an example, it is known that the resin mixture color of the remaining printing resin in the printing groove after the printing of the i-th tooth restoration layer is (and the target color {L} printed in the i-th tooth restoration layer) i a i b i (Keep this consistent) and total volume V res(i) And the target color {L} of the (i+1)th tooth restoration layer i+1 a i+1 b i+1Based on the pre-calibrated color values ​​of four color-matching resins (first resin, second resin, third resin, and fourth resin) (recorded using the L, a, and b parameters in the CIE Lab color space) and a pre-built color mixing model, the resin mixing color and total volume V of the remaining printing resin in the print chamber after the i-th tooth restoration layer is printed are determined. res(i) Using the target color {L} of the (i+1)th tooth restoration layer i+1 a i+1 b i+1 The objective of solving the color mixing model is to determine the amount of color replenishment Δv of the first, second, third, and fourth resins that need to be added to the printing tank. 1(i+1) Δv 2(i+1) Δv 3(i+1) and Δv 4(i+1) In this embodiment, when determining the amount of each color-matching resin required for printing the current dental restoration layer, a color-matching supplement constraint is set for the total color-matching supplement amount. The color-matching supplement constraint includes: the volume ratio of the total color-matching supplement amount to the total volume of printing resin remaining in the printing chamber after the previous printing is less than a preset volume ratio threshold; the volume ratio threshold is preferably a specific value between 20% and 40%.

[0079] The volume ratio of the total amount of color-matching resin replenished to the total volume of printing resin remaining in the printing tank after the previous printing is limited to below a certain threshold. During the replenishment of color-matching resin into the printing tank, the volume fluctuation of the printing resin within the tank is minimal, ensuring a stable physical state and guaranteeing the quality of the 3D printed product. In this embodiment, because the target color of each dental restoration layer is darker (lower brightness value) than the target color of the previous layer, and the remaining printing resin in the printing tank is not completely replaced, the aforementioned interlayer recursive method allows the resin mixture color in the printing tank to gradually deepen as the printing process progresses, ultimately maintaining consistency with the color gradient trend of the tooth from the incisal edge of the crown to the neck.

[0080] Step S52: After the printing resin is replenished according to the specified color matching amount, with the desired radial saturation distribution as the curing target, the exposure parameters for 3D printing are determined according to a pre-set exposure control strategy. Based on the exposure parameters, the dental restoration layer is 3D printed. The printing program is used to control the lifting and lowering of the printing platform and to control the mixing structure to disperse and mix the printing resin in the printing tank evenly. The mixing structure can be a mechanical stirring structure or a vibration dispersion structure.

[0081] This embodiment utilizes a cross-sectional plane orthogonal to the crown height direction to obtain the cross-sectional profile of the center height of the dental restoration layer; based on the cross-sectional profile, a desired radial saturation distribution is determined, which characterizes the correspondence between radial position points on the cross-sectional profile and the desired saturation; based on a pre-constructed correlation table between saturation and exposure energy, the required exposure energy for each radial position point on the cross-sectional profile is determined according to the desired radial saturation distribution; based on the required exposure energy for each radial position point, the exposure parameters for 3D printing are determined. When printing is required, the printing platform is controlled to move to the corresponding height of the dental restoration layer, and the cross-section of the dental restoration layer is subjected to pixel-level exposure and curing according to the printing program set by the exposure parameters.

[0082] Among them, combined Figure 3 For each dental restoration layer, the cross-sectional profile is discretized into multiple radial position points from the side near the labial / buccal outer surface towards the side near the pulp cavity; the desired radial saturation distribution is constructed according to the characteristics of natural teeth: "low saturation on the outer side and high saturation on the inner side". In this embodiment, to avoid the excessive impact of exposure energy changes on curing depth and dimensional accuracy, the exposure energy is preferably limited to ±20% of the reference exposure energy, and the overall curing degree can be compensated by the post-curing process (after the printed part is removed and cleaned, it will be placed in a curing chamber for secondary curing).

[0083] Combination Figure 4 Another specific embodiment provides a 3D printing system for gradient-colored dental restorations, which includes:

[0084] The identification module is used to acquire tooth color change data along the crown height direction on the labial surface of healthy adjacent teeth for the target tooth to be repaired; in some embodiments, the tooth color change data can be acquired by a digital impression device or a high-resolution oral camera.

[0085] A slicing module is used to slice a pre-constructed prosthetic model of the target tooth to obtain multiple dental restoration layers; in some embodiments, the slicing module includes dental 3D printing slicing software running on a PC or workstation.

[0086] The color determination module is used to determine the target color of each tooth restoration layer in the restoration model by referring to the tooth color change data of the labial side of healthy adjacent teeth.

[0087] The sequence determination module is used to sort the target colors of all dental restoration layers according to a rule from light to dark as the printing order;

[0088] The printing module is used to print each tooth restoration layer of the restoration model in three dimensions according to the printing order, based on the target color and a pre-set color matching feeding strategy and exposure control strategy, to obtain a gradient-colored tooth restoration of the target tooth. In some embodiments, the printing module includes a 3D printer body and the four feeding components. The four feeding components are used to feed the first resin, the second resin, the third resin and the fourth resin, respectively. Each feeding component includes a resin tank, a metering pump or a stepper motor driven syringe, a delivery pipeline, etc., which can quantitatively deliver the corresponding volume of resin to the printing tank according to the feeding program.

[0089] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0090] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0091] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0092] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0093] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for three-dimensional printing of a graded color dental restoration, characterized in that, The method comprises the following steps: obtaining tooth color change data of a healthy adjacent tooth along a labial surface of the healthy adjacent tooth in a direction of a height of a tooth crown for a target tooth to be repaired; slicing a restoration model of the target tooth to obtain a plurality of tooth restoration layers; determining a target color of each tooth restoration layer of the restoration model according to the tooth color change data of the labial surface of the healthy adjacent tooth; sorting the target colors of all the tooth restoration layers according to a rule of from light to dark as a printing order; performing three-dimensional printing on each tooth restoration layer of the restoration model in the printing order according to a preset color matching and feeding strategy and an exposure control strategy, and taking the target color as a printing target to obtain a gradient color tooth restoration body of the target tooth; performing three-dimensional printing on each tooth restoration layer of the restoration model in the printing order according to the preset color matching and feeding strategy and the exposure control strategy comprises: before printing each tooth restoration layer, determining a color matching supplement amount of each color matching resin according to the preset color matching and feeding strategy, taking the target color of the tooth restoration layer as a color matching target; after the printing resin in a printing tank is supplemented according to the color matching supplement amount, determining an exposure parameter of the three-dimensional printing according to the preset exposure control strategy, taking a desired radial saturation distribution as a solidification target, and performing three-dimensional printing on the tooth restoration layer based on the exposure parameter; determining the color matching supplement amount of each color matching resin according to the preset color matching and feeding strategy comprises: for the first printed tooth restoration layer: determining the color matching supplement amount of each color matching resin required for printing the current tooth restoration layer, taking the target color of the tooth restoration layer as a color matching target; for each subsequent printed tooth restoration layer: before the printing of the current tooth restoration layer starts, determining the color matching supplement amount of each color matching resin required for printing the current tooth restoration layer according to the resin mixing color and the total volume of the remaining printing resin in the printing tank after the last printing ends, taking the target color of the current tooth restoration layer as a color matching target.

2. The method according to claim 1, wherein The tooth color change data comprises a tooth color change function representing a mapping relationship between a tooth height and a tooth color.

3. The method of claim 1, wherein the method further comprises: The slicing to obtain a plurality of tooth restoration layers comprises: adopting equidistant slicing to obtain a plurality of tooth restoration layers with the same thickness.

4. The method of claim 1, wherein the method further comprises: The determining of the target color of each tooth restoration layer of the restoration model according to the tooth color change data of the healthy adjacent tooth comprises: for each tooth restoration layer, determining a reference tooth height on the labial surface of the healthy adjacent tooth corresponding to the current tooth restoration layer according to a relative height position of the current tooth restoration layer between a coronal incisal end and a cervical position of the restoration model; taking a tooth color corresponding to the reference tooth height in the tooth color change data as the target color of the current tooth restoration layer.

5. The method of claim 1, wherein the method further comprises: The tooth color comprises a lightness value. The sorting of the target colors of all the tooth restoration layers according to the rule of from light to dark as the printing order comprises: sorting the target colors of all the tooth restoration layers according to an order of from high to low of the lightness values as the printing order.

6. The method of claim 1, wherein the method further comprises: The color matching supplement constraint condition is set for the total color matching supplement amount, which is the sum of the color matching supplement amounts of the various color matching resins. The color matching supplement constraint condition includes that the volume ratio of the total color matching supplement amount to the total volume of the remaining printing resin in the printing tank after the last printing ends needs to be less than a preset volume ratio threshold.

7. The method of claim 1, wherein the method further comprises: The total volume of the remaining printing resin in the printing tank is updated after each dental restoration layer printing ends, and the updating method includes: For the first printed dental restoration layer: The total volume of the remaining printing resin in the printing tank after the current dental restoration layer printing ends is determined according to the difference between the total color matching supplement amount and the resin consumption amount of this printing; For each subsequent printed dental restoration layer: Based on the total volume of the remaining printing resin in the printing tank after the last printing ends, the total volume of the remaining printing resin in the printing tank after this printing ends is determined according to the difference between the total color matching supplement amount and the resin consumption amount of this printing; The total color matching supplement amount is the sum of the color matching supplement amounts of the various color matching resins.

8. The method of claim 1, wherein the method further comprises: The resin mixed color of the remaining printing resin in the printing tank is updated after each dental restoration layer printing ends, and the updating method includes: The target color of this printing is taken as the resin mixed color of the remaining printing resin in the printing tank after this printing ends.

9. The method of claim 1, wherein the method further comprises, The dental color includes red-green axis coordinate values, yellow-blue axis coordinate values, and lightness values, and the color matching resin includes a first resin, a second resin, a third resin, and a fourth resin; Increasing the volume ratio of the first resin in the printing resin in the printing tank can make the red-green axis coordinate value of the resin mixed color of the printing resin in the printing tank shift towards the red direction; Increasing the volume ratio of the second resin in the printing resin in the printing tank can make the yellow-blue axis coordinate value of the resin mixed color of the printing resin in the printing tank shift towards the yellow direction; Increasing the volume ratio of the third resin in the printing resin in the printing tank and decreasing the volume ratio of the fourth resin in the printing resin in the printing tank can increase the lightness value of the resin mixed color of the printing resin in the printing tank.

10. The method of claim 1, wherein the method further comprises: Taking the expected radial saturation distribution as the solidification target, the exposure parameters of three-dimensional printing are determined according to a pre-set exposure control strategy, including: Obtaining the cross-sectional profile of the center height of the dental restoration layer using a cross-section plane orthogonal to the crown height direction; Determining the expected radial saturation distribution according to the cross-sectional profile, which represents the correspondence between the radial position points on the cross-sectional profile and the expected saturation; Based on a pre-constructed saturation-exposure energy correlation table, determining the exposure energy required by each radial position point on the cross-sectional profile according to the expected radial saturation distribution; Determining the exposure parameters of three-dimensional printing according to the exposure energy required by each radial position point.

11. A system for three-dimensional printing of a graded color dental restoration, characterized in that The gradient color dental restoration three-dimensional printing system for performing the gradient color dental restoration three-dimensional printing method of any one of claims 1-10, including: An identification module, configured to obtain dental color change data of a healthy adjacent tooth labial surface along a crown height direction for a target tooth to be repaired; The slice module is configured to slice the pre-constructed restoration model of the target tooth to obtain a plurality of tooth restoration layers; The color determination module is configured to determine the target color of each tooth restoration layer of the restoration model by referring to the tooth color change data of the healthy adjacent tooth labial surface; The sequence determination module is configured to sort the target colors of all the tooth restoration layers according to the rule from light to deep as the printing sequence; The printing module is configured to take the target color as the printing target, and perform three-dimensional printing on each tooth restoration layer of the restoration model in sequence according to the printing sequence based on the pre-set color matching supply strategy and exposure control strategy to obtain the gradient color tooth restoration body of the target tooth.

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