Movable denture support 3D printing method based on bionic design

Abstract

The invention relates to the technical field of denture support printing, in particular to a removable denture support 3D printing method based on bionic design, which comprises the following steps: obtaining structural information of dentition, periodontal membrane and alveolar bone; performing three-dimensional reconstruction in medical image processing software to generate triangular patch models of dentition, periodontal membrane and alveolar bone; finite element analysis is operated, the tooth occlusion force, the stress concentration area and the stress distribution of the periodontal membrane of the triangular patch model under the given load and boundary conditions are calculated, and a biomechanical model is generated; designing a three-dimensional model of the removable denture bracket according to the biomechanical model; the triangular patch model is subjected to bionic analysis by loading boundary conditions and loads to obtain the biomechanical model, and the stent is designed according to stress analysis of the biomechanical model, so that the overall strength of the printed stent is more adaptive to occlusal force of a user, and the printed stent has better durability and better wearing comfort of the user.

Description

Technical Field

[0001] The present invention relates to the technical field of denture framework printing, and in particular to a 3D printing method for removable denture frameworks based on bionic design. Background Art

[0002] A removable denture framework is a prosthesis that can be removed and worn by itself. It uses the remaining natural teeth, the mucosa and bone tissue under the denture base as support, relies on the retainers and denture base of the denture for retention, restores the shape and function of the missing teeth with artificial teeth, and restores the shape of the defective alveolar ridge, jawbone and its surrounding soft tissues with denture base materials.

[0003] Since the bite force of each tooth is different, the stress distribution of the periodontal ligament has concentrated areas and dispersed areas. Traditional manual methods and primary digital means cannot perform bionic analysis on the model, and the produced frameworks are not only not durable, but also affect the wearing comfort of patients. Summary of the Invention

[0004] In view of the problems existing in the above-mentioned existing 3D printing method for removable denture frameworks based on bionic design, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to provide a 3D printing method for removable denture frameworks based on bionic design.

[0006] To solve the above technical problems, the present invention provides the following technical solution: A 3D printing method for removable denture frameworks based on bionic design, comprising:

[0007] Obtain a dental cast model, and use micro-CT to scan the dental cast model to obtain the structural information of the dentition, periodontal ligament and alveolar bone;

[0008] Import the data obtained by micro-CT scanning into medical image processing software for three-dimensional reconstruction to generate a triangular facet model of the dentition, periodontal ligament and alveolar bone;

[0009] Run finite element analysis to calculate the tooth biting force, stress concentration area and stress distribution of the periodontal ligament of the triangular facet model under given loads and boundary conditions, and generate a biomechanical model;

[0010] Import the biomechanical model into design software and design a three-dimensional model of the removable denture framework according to the biomechanical model;

[0011] Perform smoothing processing on the three-dimensional model of the removable denture framework;

[0012] Calibrate the 3D printing device, import the smoothed three-dimensional model and execute the printing operation to obtain a removable denture framework;

[0013] Immerse the removable denture framework in the lubricating fluid to ensure better conformity to the wetness of the periodontal membrane.

[0014] As a preferred embodiment of the 3D printing method of the removable denture framework based on bionic design described in the present invention, wherein: the dental arch model is obtained by the impression method or the digital oral scanning method. The specific steps of the impression method are as follows:

[0015] Tray selection: Select a round-bottomed and non-porous tray that is consistent with the shape and size of the alveolar arch.

[0016] Preliminary treatment of impression compound: Immerse the impression compound in hot water at 70 °C to soften it, and ensure uniform softening inside and outside.

[0017] Obtaining the preliminary impression: Insert the tray into the mouth, and pay attention that the tray should not be skewed when in place.

[0018] Trimming the preliminary impression: Remove the excessively long, excessive, and thick parts of the edge of the preliminary impression. After softening it with an alcohol lamp or a spray gun, insert it into the mouth again for myofunctional trimming.

[0019] Obtaining the final impression: Make corresponding buffering for the upper and lower jaw buffer areas before taking the final impression, that is, scrape off part of the preliminary impression material. After mixing the preliminary impression material, place it on the individual tray of the impression compound, and take the upper and lower jaw final impressions in the same way as taking the preliminary impression, and perform myofunctional trimming on the edge of the impression. Take it out after solidification.

[0020] Pouring the model and demolding and trimming: Mix the gypsum slurry, pour the gypsum slurry into the entire impression, and trim it after the gypsum heats up and solidifies.

[0021] As a preferred embodiment of the 3D printing method of the removable denture framework based on bionic design described in the present invention, wherein: the length of the tray should exceed the palatine fovea by 2-4 mm in the upper jaw, cover the pterygomaxillary notch on both sides, and cover the retromolar pad in the lower jaw.

[0022] The width of the tray should be 2-3 mm wider than the alveolar ridge, and the peripheral height should be about 2 mm away from the labial, buccal, and lingual grooves.

[0023] As a preferred embodiment of the 3D printing method of the removable denture framework based on bionic design described in the present invention, wherein: the three-dimensional reconstruction includes image processing and three-dimensional modeling;

[0024] Image processing is used to process the image and extract necessary features;

[0025] Three-dimensional modeling uses stereoscopic vision technology to convert the necessary features into three-dimensional point cloud data and generate a triangular patch model of the dentition, periodontal membrane, and alveolar bone.

[0026] As a preferred embodiment of the 3D printing method of the removable denture framework based on bionic design described in the present invention, wherein: the image processing includes:

[0027] Segmentation: Create a new layer in Mimics, select an appropriate threshold to cover the dentition, periodontal ligament, and alveolar bone edge, use the Region Grow tool to extract the dentition, periodontal ligament, and alveolar bone images, and remove debris in the images;

[0028] Denoising: Perform denoising processing on the image using Gaussian filtering to eliminate noise in the image;

[0029] Feature extraction: Use a feature point detection algorithm to identify necessary features in the picture, where the necessary features include natural dentition, oral position, periodontal ligament, and alveolar bone information.

[0030] As a preferred solution of the 3D printing method for the removable denture bracket based on bionic design described in the present invention, wherein: The specific method of finite element analysis is as follows:

[0031] Import the triangular facet model into Geomagic Warp software in STL format, use the free mesh generation algorithm, with the minimum internal angle of the element taken as 25° as the constraint condition, mesh the triangular facet model to obtain a three-dimensional finite element model of the dentition, periodontal ligament, and alveolar bone composed of 10-node tetrahedral elements;

[0032] Apply corresponding boundary conditions and loads on the three-dimensional finite element model to obtain the tooth biting force, stress concentration area, and stress distribution of the periodontal ligament.

[0033] As a preferred solution of the 3D printing method for the removable denture bracket based on bionic design described in the present invention, wherein: The boundary conditions and loads include:

[0034] Vertical load: A linear force applied on the tooth biting surface, used to simulate the force borne by the teeth during chewing;

[0035] Oblique load: A force applied on the tooth surface that is not perpendicular to the biting surface, used to simulate the lateral force received by the teeth during chewing, so that a higher stress concentration occurs at the root part;

[0036] Concentrated load: A force applied on a specific biting area, usually used to simulate a specific biting contact point to analyze the stress and displacement conditions at this part;

[0037] Dynamic load: A load applied on the model that changes with time, used to simulate the change of force during chewing, and used to analyze the stress and displacement borne by the periodontal ligament during dynamic chewing.

[0038] As a preferred solution of the 3D printing method for the removable denture bracket based on bionic design described in the present invention, wherein: When designing according to the biomechanical model, perform local reinforcement on the stress concentration area, and adjust the printing layer thickness parameter or increase the support structure parameter;

[0039] Adjust the printing layer thickness parameter or the geometric shape parameter for the stress dispersion area.

[0040] As a preferred solution of the 3D printing method for the removable denture bracket based on bionic design described in the present invention, wherein: the smoothing process adopts mesh subdivision to determine the accuracy of the graphic distribution in the three-dimensional model of the removable denture bracket, and by adjusting this parameter, the display accuracy of internal force, deformation or stress in the result diagram is controlled.

[0041] As a preferred solution of the 3D printing method for the removable denture bracket based on bionic design described in the present invention, wherein: the lubricating fluid adopts polysorbate solution.

[0042] The beneficial effects of the present invention: The present invention performs bionic analysis on the triangular facet model by loading boundary conditions and loads to obtain a biomechanical model, and designs the bracket according to the stress analysis of the biomechanical model, so that the overall strength of the printed bracket is more adapted to the biting force of the user, has better durability, and at the same time the wearing comfort of the user is better, improving the overall user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0044] Figure 1 It is a schematic flow framework diagram of the 3D printing method for the removable denture bracket based on bionic design of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following will make a detailed description of the specific embodiments of the present invention in conjunction with the drawings in the specification.

[0046] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0047] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The "in one embodiment" that appears in different places in this specification does not all refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0048] Next, the present invention will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally in a non-general proportion, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0049] Embodiment 1

[0050] Referring to Figure 1 , a 3D printing method for a removable denture bracket based on bionic design is provided, including:

[0051] Obtaining a dental arch model;

[0052] The dental arch model adopts the impression method, and the specific steps of the impression method are as follows:

[0053] Tray selection: Select a round-bottomed and hole-free tray that is consistent with the shape and size of the alveolar arch;

[0054] Pretreatment of impression compound: Put the impression compound into hot water at 70°C to soak and soften it, and require uniform softening inside and outside. When taking the upper jaw, knead an appropriate amount of impression compound into a ball and place it on the upper jaw tray. The alveolar ridge area is slightly concave, the surface is smooth, and the impression compound slightly wraps around the tray edge to prevent falling off. When taking the lower jaw, knead the impression compound into a strip and place it on the tray;

[0055] Obtaining the primary impression: Insert the tray into the mouth, pay attention that the tray should not be skewed when in place, the alveolar ridge in the anterior tooth area should be in place first, the tray handle is aligned with the tip of the nose, and at the same time, press with the middle fingers of both hands on both sides to make the tray fully in place, and then perform the muscle function movement of the lips, cheeks, and tongue. After cooling, take it out to obtain the primary impression;

[0056] Trimming the primary impression: Cut off the parts of the primary impression with too long, too much, and too thick edges. After softening it with an alcohol lamp or a spray gun, place it in the mouth again for muscle function trimming. For the insufficient edges, add impression compound, soften it with a fire and perform muscle function trimming in the mouth;

[0057] Obtaining the final impression: Make corresponding buffering for the upper and lower jaw buffer areas before taking the final impression, that is, scrape off part of the primary impression material. The final impression often uses impression materials with greater fluidity, such as alginate impression materials. After mixing the impression material, place it on the individual tray of the impression compound, and take the upper and lower jaw final impressions in the same way as taking the primary impression, and perform good muscle function trimming on the impression edges. After solidification, take it out;

[0058] Pouring model and demolding and trimming: Mix the plaster. Slowly add the plaster powder into a rubber bowl containing an appropriate amount of water. The ratio of water to plaster is about 1:2. Stir evenly with a mixing knife and vibrate to expel air. When pouring the mold, take a small amount of the prepared plaster and place it at the higher part of the palate or lingual side of the impression. Hold the tray with the left hand and gently vibrate it to make the plaster flow into the crown part of the impression. Continue to pour the plaster until the entire impression is filled;

[0059] After pouring the mold, let it stand for about half an hour. After the plaster heats up and solidifies, trim the periphery of the model and the protruding part of the mandibular lingual side plaster. Use a wax knife to cut into the model along the posterior margin line. The cutting depth is: about 2 mm on both sides of the median palatine suture area, about 1 mm in the pterygomaxillary notch area, and about 0.5 mm in the median palatine suture area. Then, according to different widths in different parts, with the posterior boundary as the deepest part, gradually become shallower forward and cut into a slope shape;

[0060] Specifically, the length of the tray should exceed the palatine fovea by 2 - 4 mm in the maxilla, cover the pterygomaxillary notch on both sides, and cover the retromolar pad in the mandible;

[0061] The width of the tray should be 2 - 3 mm wider than the alveolar ridge, and the peripheral height is about 2 mm away from the labial, buccal, and lingual grooves;

[0062] The dental cast model is obtained by the digital oral scanning method. The specific acquisition method is as follows:

[0063] Equipment: Use 3Shape, TRIOS or iTero;

[0064] Oral cleaning: Brush teeth before scanning. Thoroughly clean the oral cavity with clean water or oral mouthwash to remove food residues, soft deposits and other impurities. For patients with dental calculus, ultrasonic scaling is required to avoid excessive dental calculus affecting the accuracy of data acquisition;

[0065] Positioning: Gently place the probe of the equipment into the oral cavity and select the posterior tooth area as the starting point because the posterior tooth area is relatively stable and has a large area, which is convenient for preliminary positioning and obtaining sufficient scanning data;

[0066] Scanning: During the scanning process, the probe needs to be moved slowly and smoothly to ensure that the light of the probe can cover all surfaces of the teeth and gums, including the occlusal surface, buccal surface, lingual surface and gingival margin. Among them, when scanning the occlusal surface of the teeth, the probe should be perpendicular to the occlusal surface to obtain accurate details such as cusp tips and fissures; when scanning the buccal surface and lingual surface, the probe should be at an appropriate angle with the tooth surface, generally about 30 - 60 degrees, so as to better capture the texture and shape of the tooth surface;

[0067] To obtain a complete oral model, scans need to be taken from different angles. In addition to scanning from the buccolingual direction, mesiodistal scans are also required. For multiple adjacent teeth, the scan should gradually move from the mesial of one tooth to the distal of the other tooth on the same side, and attention should be paid to scanning the occlusion relationship between the upper and lower teeth.

[0068] Modeling: After the scan is completed, the data will be processed by the software provided with the device, and multiple scanned segments will be stitched together. This stitching process is automatically completed based on the overlapping parts and feature points between the scanned segments. For example, if the same part of adjacent teeth appears in different scanned segments, the software will stitch the segments together according to these repeated features.

[0069] After the stitching is completed, noise removal is performed to make the model surface smoother. At the same time, the color of the model will also be adjusted, usually according to the actual colors of the teeth and gums for matching to make the model more realistic.

[0070] Micro-CT is used to scan the dental and jaw model to obtain the structural information of the dentition, periodontal ligament, and alveolar bone.

[0071] The data obtained from micro-CT scanning is imported into medical image processing software (such as Mimics17) for three-dimensional reconstruction to generate a triangular facet model of the dentition, periodontal ligament, and alveolar bone.

[0072] Furthermore, three-dimensional reconstruction includes image processing and three-dimensional modeling.

[0073] Image processing is used to process the images and extract necessary features.

[0074] Three-dimensional modeling uses stereovision technology to convert the necessary features into three-dimensional point cloud data and generate a triangular facet model of the dentition, periodontal ligament, and alveolar bone.

[0075] Specifically, image processing includes:

[0076] Segmentation: Create a new layer (Mask) in Mimics, select an appropriate threshold to cover the edges of the dentition, periodontal ligament, and alveolar bone, and use the Region Grow tool to extract the images of the dentition, periodontal ligament, and alveolar bone and remove the debris in the images.

[0077] Despiking: Gaussian filtering is used to denoise the images and eliminate the noise in the images.

[0078] Feature extraction: Feature point detection algorithms are used to identify the necessary features in the pictures, where the necessary features include natural dentition, oral position, periodontal ligament, and alveolar bone information.

[0079] Run a finite element analysis to calculate the occlusal force, stress concentration areas, and stress distribution of the periodontal ligament of the triangular facet model under given loads and boundary conditions, and generate a biomechanical model;

[0080] The specific method of the finite element analysis is as follows:

[0081] Import the triangular facet model in STL format into Geomagic Warp software, and use the free mesh generation algorithm. With the constraint that the minimum interior angle of the element is 25°, mesh the triangular facet model to obtain a three-dimensional finite element model of the dentition, periodontal ligament, and alveolar bone composed of 10-node tetrahedral elements;

[0082] Apply the corresponding boundary conditions and loads to the three-dimensional finite element model to obtain the occlusal force, stress concentration areas, and stress distribution of the periodontal ligament;

[0083] Specifically, the boundary conditions and loads include:

[0084] Material conditions: Specify the strength of human teeth and the strength of the periodontal ligament;

[0085] Displacement boundary conditions: Conditions for specifying displacements on the tooth boundaries of the model; for example, the displacements on the tooth boundaries can be fixed, or the magnitude and direction of the displacements on the tooth boundaries can be specified. These conditions simulate the constraints in the real system, such as the zero-displacement boundary condition simulating the fixed support of the system;

[0086] Force boundary conditions: Conditions for specifying forces on the tooth and periodontal ligament boundaries of the model. These forces can be concentrated forces, distributed forces, or surface pressures;

[0087] Pressure boundary conditions: Conditions for specifying pressures on the tooth and periodontal ligament boundaries of the model. These pressures can be body forces or surface forces;

[0088] Vertical load: A linear force applied to the occlusal surface of the tooth to simulate the force borne by the tooth during chewing;

[0089] Oblique load: A force applied to the tooth surface that is not perpendicular to the occlusal surface, used to simulate the lateral force on the tooth during chewing, causing higher stress concentration at the root part of the tooth;

[0090] Concentrated load: A force applied to a specific occlusal area, usually used to simulate a specific occlusal contact point to analyze the stress and displacement conditions at that location;

[0091] Dynamic load: A load applied to the model that changes with time, used to simulate the change in force during chewing, and used to analyze the stress and displacement borne by the periodontal ligament during dynamic chewing.

[0092] Import the biomechanical model into the design software and design the 3D model of the removable denture bracket according to the biomechanical model;

[0093] Specifically, when designing according to the biomechanical model, local reinforcement is carried out for the stress concentration area, and the printing layer thickness parameter or the support structure parameter is adjusted;

[0094] For the area where stress is dispersed, adjust the printing layer thickness parameter or adjust the geometric shape parameter.

[0095] Calibrate the 3D printing device, import the smoothed 3D model and execute the printing operation to obtain the removable denture bracket.

[0096] This method conducts bionic analysis on the triangular facet model by loading boundary conditions and loads to obtain the biomechanical model, and designs the bracket according to the stress analysis of the biomechanical model, so that the overall strength of the printed bracket is more suitable for the biting force of the user, has better durability, and at the same time the wearing comfort of the user is better, improving the overall user experience.

[0097] Example 2

[0098] What is different about this example from the first example is that the 3D printing method of the removable denture bracket based on bionic design disclosed in this example further includes: performing smoothing processing on the 3D model of the removable denture bracket before 3D printing;

[0099] Specifically, the smoothing processing adopts mesh subdivision to determine the accuracy of the graphic distribution in the 3D model of the removable denture bracket, and by adjusting this parameter, the display accuracy of internal force, deformation or stress in the result diagram is controlled.

[0100] Through smoothing processing, the model accuracy can be improved, the stress distribution can be made more accurate, and the overall strength of the printed removable denture bracket can be ensured.

[0101] The remaining structures are the same as those in Example 1.

[0102] Example 3

[0103] What is different about this example from the above examples is that the 3D printing method of the removable denture bracket based on bionic design disclosed in this example further includes: immersing the printed removable denture bracket in a lubricating fluid to ensure its better fit with the wetness of the periodontal membrane.

[0104] The lubricating fluid uses polysorbate solution;

[0105] Specifically, the composition of the polysorbate solution is as follows:

[0106] Every 1 mole of sorbitol or the corresponding sorbitan will add 20 moles of ethylene oxide.

[0107] The printed removable denture framework is immersed in the polysorbate solution, which can form a softening film on its surface, ensuring that the surface of the removable denture framework is more moist and smooth, more comfortable to wear after being worn, and will not cause damage to the periodontal membrane due to friction.

[0108] All the other structures are the same as those in Embodiment 2.

[0109] Importantly, it should be noted that the construction and arrangement of the present application shown in multiple different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who refer to this disclosure should easily understand that many modifications are possible without materially departing from the novel teachings and advantages of the subject matter described in this application (for example, changes in the dimensions, scales, structures, shapes and proportions of various elements, and parameter values (such as temperature, pressure, etc.), installation arrangements, use of materials, colors, orientations, etc.). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature or number or position of discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. In the claims, any "means-plus-function" clause is intended to cover the structures described herein that perform the recited function, and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present invention. Therefore, the present invention is not limited to a particular embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0110] In addition, in order to provide a concise description of the exemplary embodiments, all features of the actual embodiments may not be described (i.e., those features that are not relevant to the currently considered best mode of implementing the present invention or those features that are not relevant to the implementation of the present invention).

[0111] It should be understood that in the development of any actual implementation, such as in any engineering or design project, a large number of specific implementation decisions may be made. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, without excessive experimentation, such development efforts will be a routine task of design, manufacturing and production.

[0112] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered by the scope of the claims of the present invention.

Claims

1. A 3D printing method for a removable denture bracket based on bionic design, characterized in that: include: Obtain a dental model and use micro-CT to scan the dental model to obtain the structural information of the dentition, periodontal membrane, and alveolar bone; The data obtained from the micro-CT scan is imported into the medical image processing software for three-dimensional reconstruction to generate triangular facet models of the dentition, periodontal membrane and alveolar bone; Run finite element analysis to calculate the tooth occlusal force, stress concentration area, and stress distribution of the periodontal membrane under given loads and boundary conditions of the triangular patch model to generate a biomechanical model; Import the biomechanical model into the design software, and design a three-dimensional model of the removable denture framework according to the biomechanical model; Smoothing the three-dimensional model of the removable denture framework; Calibrate the 3D printing equipment, import the smoothed 3D model and perform the printing operation to obtain the removable denture framework; Immerse the removable denture frame in lubricating fluid to ensure that it fits better with the moisture of the periodontal membrane.

2. The 3D printing method for a removable denture bracket based on bionic design according to claim 1, characterized in that: The dental model is obtained by the impression method or the digital oral scanning method. The specific steps of the impression method are as follows: Tray selection: Choose a round-bottomed, non-porous tray that matches the shape and size of the alveolar arch; Impression paste pretreatment: Soak the impression paste in 70℃ hot water to soften it, and make sure it softens evenly inside and outside. Initial impression making: Introduce the tray into the mouth, making sure that the tray does not tilt when in place; Trimming of the initial impression: the overlong, excessive, and thick parts of the edge of the initial impression are trimmed off, softened with an alcohol lamp or a spray gun, and then repositioned in the mouth for myofunctional trimming; Final impression preparation: before making the final impression, the upper and lower mandibular buffer zones are used for corresponding buffering, that is, part of the initial impression material is scraped off, the initial impression material is mixed and placed on individual trays of impression paste, and the upper and lower mandibular final impressions are taken in the same way as the initial impressions, and the muscle function of the impression edge is trimmed, and the impression is taken out after solidification; Pouring model and demoulding and trimming: Mix the gypsum slurry, fill the entire mold with the gypsum slurry, and then trim it after the gypsum heats up and solidifies.

3. The 3D printing method for a removable denture bracket based on bionic design according to claim 2, characterized in that: The length of the tray should exceed the palatine fossa by 2 to 4 mm in the upper jaw, cover the pterygomaxillary notch on both sides, and cover the retromolar pad in the lower jaw; The width of the tray should be 2 to 3 mm wider than the alveolar ridge, and the peripheral height should be about 2 mm away from the lip, cheek, and tongue grooves.

4. The 3D printing method for a removable denture bracket based on bionic design according to claim 3, characterized in that: Three-dimensional reconstruction includes image processing and three-dimensional modeling; Image processing is used to process images and extract necessary features; Three-dimensional modeling uses stereo vision technology to convert necessary features into three-dimensional point cloud data to generate triangular surface models of the dentition, periodontal membrane and alveolar bone.

5. The 3D printing method for a removable denture bracket based on bionic design according to claim 4, characterized in that: Image processing includes: Segmentation: Create a new layer in Mimics, select an appropriate threshold to cover the dentition, periodontal ligament, and alveolar bone margins, use the Region Grow tool to extract the dentition, periodontal ligament, and alveolar bone images, and remove debris from the image; De-noising: Use Gaussian filtering to denoise the image and eliminate the noise in the image; Feature extraction: A feature point detection algorithm is used to identify necessary features in the image, including natural dentition, oral position, periodontal membrane, and alveolar bone information.

6. The 3D printing method for a removable denture bracket based on bionic design according to claim 5, characterized in that: The specific method of finite element analysis is as follows: The triangular patch model was imported into Geomagic Warp software in STL format, and the free meshing algorithm was used to mesh the triangular patch model with the minimum internal angle of the unit set to 25° as the constraint condition, and a three-dimensional finite element model of the dentition, periodontal ligament and alveolar bone consisting of 10-node tetrahedral units was obtained. The corresponding boundary conditions and loads were applied to the three-dimensional finite element model to obtain the tooth occlusal force, stress concentration area, and stress distribution of the periodontal membrane.

7. The 3D printing method for a removable denture bracket based on bionic design according to claim 6, characterized in that: Boundary conditions and loads include: Vertical load: A linear force applied to the occlusal surface of the tooth to simulate the forces on the teeth during chewing; Oblique load: A force applied to the tooth surface that is not perpendicular to the occlusal surface. It is used to simulate the lateral force on the teeth during chewing, causing a higher stress concentration on the root of the tooth. Concentrated load: A force applied to a specific occlusal area, usually used to simulate a specific occlusal contact point to analyze the stress and displacement of that area; Dynamic load: A time-varying load applied to the model to simulate the change in force during chewing and to analyze the stress and displacement of the periodontal ligament during dynamic chewing.

8. The 3D printing method for a removable denture bracket based on bionic design according to claim 7, characterized in that: When designing according to the biomechanical model, local reinforcement is performed on stress concentration areas, and the printing layer thickness parameters are adjusted or the support structure parameters are increased; For areas where stress is dispersed, adjust the printing layer thickness parameters or adjust the geometric shape parameters.

9. The 3D printing method for a removable denture bracket based on bionic design according to claim 8, characterized in that: Smoothing uses mesh subdivision to determine the accuracy of the graphic distribution in the three-dimensional model of the removable denture framework. By adjusting this parameter, the display accuracy of the internal force, deformation or stress in the result diagram can be controlled.

10. The 3D printing method for a removable denture bracket based on bionic design according to claim 9, characterized in that: The lubricating fluid is a polysorbate solution.

Images