Method for constructing giant panda dental pulp and tooth body repair model and giant panda dental pulp and tooth body repair model

Abstract

The invention discloses a method for constructing a giant panda dental pulp and tooth body repair model and the model, and belongs to the technical field of giant panda tooth research, and the method comprises the following steps: assembling giant panda canine teeth made of different post-core-crown materials, and carrying out stress analysis on premolar teeth and molar teeth; establishing a canine tooth wear model, a premolar wear model and a molar wear model when different dental crown materials are worn, and outputting tooth morphology feature changes along with tooth chewing; and outputting the optimal dental pulp and tooth body repair material results of panda canine teeth, premolar teeth and molar teeth. According to the method, the abrasion resistance of the panda teeth is tested through stress analysis of the panda canine teeth, the premolar teeth and the molar teeth assembled with different post-core crown materials and by establishing canine tooth abrasion models, premolar tooth abrasion models and molar tooth abrasion models when different dental crown materials are worn, and abrasion visualization can be achieved. Finally, the optimal dental pulp and tooth repairing material result of panda canine teeth, premolar teeth and molar teeth can be output.

Description

Technical Field

[0001] The present invention relates to the technical field of giant panda tooth research, and in particular to a method for constructing a giant panda dental pulp and tooth restoration model and the model. Background Art

[0002] Giant pandas have four types of teeth: incisors, canines, premolars, and molars. Subtle changes in these teeth significantly reflect the gradual specialization of the giant panda's diet. From the early panda to the modern giant panda, the premolar and molar lingual cusps have become increasingly developed, while the chewing surfaces of the molars have become increasingly lumpy. Premolars, in particular, have developed towards a grinding pattern, as evidenced by the increasingly developed premolar and premolar cusps.

[0003] The health of giant pandas' teeth is a significant factor influencing their physique, lifespan, and population size. Dental disease or wear can lead to decreased or even loss of tooth function, impairing their feeding and digestion, leading to malnutrition, decreased immunity, and even systemic organ damage. Due to the extreme toughness of bamboo fiber, tooth defects are common in giant pandas. While research on endodontic restoration techniques for humans is mature, research on endodontic restoration techniques for giant pandas has yet to emerge. In the field of biomechanics, finite element analysis is an effective experimental method for simulating the mechanical functions of animal body structures. By establishing three-dimensional finite element models, assigning mechanical properties to the model materials, and reasonably simulating in vivo conditions, effective analysis of stress / strain, modal analysis, and external impact response fatigue can be performed on experimental animal structures. Finite element models are increasingly widely used due to their ability to reconstruct irregular and complex material properties and easily simulate complex boundary structures under static or dynamic loading.

[0004] At present, the number of giant panda teeth available for research is extremely small, and most of them are encased in hard jaw bones. Since giant pandas and related specimens are not allowed to undergo destructive research, research methods that cause damage to specimens, such as the "grinding method", are not suitable for studying giant panda tooth wear. With the development of finite element technology, the present invention uses finite element technology to perform force analysis on giant panda teeth without destroying the teeth to study the mechanical properties of different post and core crown materials, which is helpful for providing a reference for the selection of post and core crown materials for the pulp restoration of giant pandas. Research on giant panda dental pulp restoration technology is of great significance for the prevention and treatment of giant panda dental diseases and the development of special instruments for giant panda oral diseases.

[0005] Based on this, the present invention designs a giant panda dental pulp and tooth restoration model construction method and model to solve the above problems. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for constructing a giant panda dental pulp and tooth restoration model and a model.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: The method for constructing a giant panda dental pulp restoration model comprises the following steps: Step 1: Force analysis of panda canines, premolars, and molars fitted with different post and core crown materials, specifically including the following steps: 1) Post-core-crown assembly: constructing tooth models of giant panda canines, premolars, and molars fitted with different post-core-crown materials; 2) Loading bite force: The vertical bite force applied to the three giant panda teeth is set to a N for canines, b N for premolars, and c N for molars, with the direction set perpendicular to the mandible and downward. 3) Finite element analysis of tooth occlusion: Obtain the peak stress and stress contour of each tooth model after load application; Step 2: Establish canine, premolar, and molar wear models when wearing different crown materials, including settings for giant panda tooth morphology, giant panda chewing cycle, giant panda tooth chewing direction, tooth material, wear logic, wear visualization, and canvas parameter display. Output changes in tooth morphology as chewing progresses, and implement wear resistance analysis of canines, premolars, and molars wearing different crown materials. Step 3: Output the optimal restoration material results for the pulp and tooth of the giant panda's canines, premolars, and molars.

[0008] 2. The method for constructing a giant panda dental pulp restoration model according to claim 1 is characterized in that the tooth model construction method comprises: performing CT scanning on the canines, premolars and molars equipped with post and core crown materials to obtain a CT image of the giant panda's teeth; editing the mask pixels after threshold selection; then performing a region growing operation on the edited mask; then using the mask to perform a three-dimensional model calculation to generate a preliminary tooth model; performing surface smoothing and surface optimization processing on the preliminary tooth model in sequence; and finally performing model materialization to obtain a three-dimensional model of the giant panda's canines, premolars and molars.

[0009] Furthermore, in step 1, a=1030, b=1142N, and c=2005.

[0010] Furthermore, in step 2, the chewing cycle of the giant panda is set as follows: Assume that the chewing cycle of the giant panda is divided into three stages: Opening stroke: The mandible opens and moves laterally to the equilibrium side. When further opened, the mandible swings laterally and backwards to the mid-plane;

[0011] Closing stroke: When the mandible moves to the side of the chewing side, the jaw closes until the buccal side of the lower teeth is in line with the upper teeth; Friction stroke: The mandible moves backward on the lingual side toward the symmetrical position, while the chewing sides of the upper and lower teeth slide against each other and grind the food in the middle. The friction stroke ends at the symmetrical position near the end point, and the next chewing cycle begins with the next opening stroke. The specific setting of the giant panda's teeth chewing direction is: assuming that the giant panda chews in a clockwise direction, random parameters are added to the giant panda's chewing cycle, and counterclockwise chewing cycles are interspersed in the giant panda's clockwise chewing cycle.

[0012] Furthermore, in step 2, the wear logic is set as follows: Assuming the volume loss due to wear V abr and wear distance S abr and friction force F abr Proportional to: ; During the friction stroke, the tooth moves over each pixel, causing it to gradually wear down until the lower tooth reaches the starting point of the opening stroke. With each step, the damage from the friction accumulates, and when the pixel damage exceeds the defined maximum damage value, it is erased. The maximum damage value is the simulated hardness pixel storage value set in the previous step. When a pixel is erased, the next undamaged pixel below becomes part of the new occlusal surface. Once this specific pixel comes into contact with the corresponding pixel, the damage to that pixel increases again until it also exceeds the maximum damage and is erased. This process repeats, and the loss of tooth structure forms the new shape of the occlusal surface.

[0013] Furthermore, in step three, the canine wear model includes the wear model of the canine chewing bamboo horizontally and the wear model of the canine chewing bamboo vertically; the premolar wear model includes the wear model of the premolar chewing bamboo horizontally and the wear model of the premolar chewing bamboo vertically; the molar wear model includes the wear model of the molar chewing bamboo horizontally and the wear model of the molar chewing bamboo vertically.

[0014] Furthermore, the materials for the post and core crowns of canines, premolars and molars are selected from one of the following types: fiber resin post and core crown, fiber resin + zirconia crown, fiber resin + all-ceramic crown, zirconia post and core crown, zirconia post and core + all-ceramic crown, and zirconia post and core + resin crown.

[0015] Furthermore, in step three, at least 100 chewing cycles are performed when chewing bamboo in the horizontal and vertical directions, and visual images of tooth wear and the number of wear layers under multiple chewing cycles are output respectively.

[0016] Furthermore, the post and core crown restoration of the pulp of canine teeth uses fiber resin post and core + zirconia crown; the post and core crown restoration of the pulp of premolars uses fiber resin post and core or zirconia post and core combined with zirconia crown; the post and core crown restoration of the pulp of molars uses zirconia post and core crown.

[0017] In order to better achieve the purpose of the present invention, the present invention also provides a model obtained according to the giant panda dental pulp tooth body restoration model construction method.

[0018] The method of the present invention is used to establish a three-dimensional model of giant panda teeth, which has the following advantages: (1) The required equipment and technology are relatively simple, data acquisition is easy to implement, and the operability is strong. CT can directly scan the research object and then output the scan results in digital form. The error is relatively small. The entire process only takes 20 to 30 minutes, which can greatly simplify the reconstruction steps and process and improve reconstruction efficiency.

[0019] (2) The data provided by the reconstructed model is comprehensive, accurate and highly reliable. The internal and external structures of giant panda teeth are complex, and the number of ex vivo teeth is extremely rare. Most of the teeth available for study are encased in hard jaw specimens. Previous studies on giant panda teeth were limited to relatively basic methods such as general measurement, data statistics, and periapical observation. They were unable to provide data information on the internal structure of the teeth and could not fully and three-dimensionally reflect the anatomical information of giant panda teeth. Because CT thin-layer scanning technology has the advantages of accurate positioning, accurate reproduction of complex and subtle structures, and accurate and reusable scanning data. Using professional modeling software MIMICS to process CT scan image data, the constructed model is adjustable and accurate to the point, which can greatly reduce the loss of original specimen data. Using spiral CT scan images of teeth, combined with professional image generation and editing software, the three-dimensional reconstruction technology has high reliability. Similarly, using giant panda tooth scan images, combined with MIMICS image generation and editing software, the giant panda tooth model reconstructed can reflect the complex structural morphology of the actual tooth surface. This method is of great significance for the reconstruction of complex tissue morphology such as the occlusal surface and pulp cavity of giant panda teeth.

[0020] (3) It does not damage the tooth specimens, the specimens have a short life cycle, low cost, and high feasibility. The grinding method is time-consuming, damages the tooth specimens, is complex to operate, and the original data is easily lost. Obviously, this reconstruction method is not suitable for the study of giant panda tooth morphology; although laser scanning can meet the accuracy requirements, it has a scanning blind spot and cannot scan and model the internal pulp cavity structure, so the reconstruction range is limited. In addition, the cost of laser scanning equipment is high, so laser scanning cannot be widely used. Using CT to scan giant panda teeth, different densities can be scanned according to different requirements. For key research areas, small-pitch thin-layer scanning can be used, while non-key areas can be scanned with wider spacing to simplify the operation. After a CT scan of the same tooth specimen, the software can be used to repeatedly model the specimen, reducing the number of times the specimen is used and reducing the cost of specimen use.

[0021] The present invention constructs a wear model to test the wear resistance of giant panda teeth, which has the following advantages: (1) Avoided destructive research on giant panda teeth.

[0022] (2) This experiment simulates the chewing movement of giant panda teeth and the changes in tooth morphology after tooth wear. The results are richer. It can not only evaluate the wear resistance of different teeth, but also determine the parts of the teeth that are prone to wear, so as to carry out preventive repairs in advance for these parts of the giant panda.

[0023] (3) Wear can be visualized. Through different color changes, the evolution of the wear appearance of the giant panda's upper and lower teeth can be directly observed.

[0024] (4) In order to better simulate the chewing movement trajectory of the giant panda, this experiment added a random cycle to the chewing cycle to simulate the unconscious random chewing behavior of the giant panda when eating.

[0025] At the same time, the method for constructing a giant panda dental pulp restoration model of the present invention yielded the following results: The post-core-crown technique for canine dental pulp restoration is suitable for fiber resin posts and cores combined with zirconia crowns. The post-core-crown technique for premolar dental pulp restoration uses either fiber resin posts and cores or zirconia posts and cores, combined with zirconia crowns, depending on the restoration object. The post-core-crown technique for molar dental pulp restoration is suitable for alloy posts and cores combined with zirconia crowns, or zirconia posts and core crowns. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0027] Figure 1 This is the technical roadmap for the method of constructing the giant panda dental pulp and tooth restoration model of the present invention.

[0028] Figure 2 Equivalent stress distribution results of the canine teeth when a force of 1030N is applied vertically.

[0029] Figure 3 Equivalent stress distribution results of the premolar when a force of 1142N is applied vertically.

[0030] Figure 4 Equivalent stress distribution results of the molar when a force of 2005N is applied vertically.

[0031] Figure 5 Diagram showing canine teeth undergoing 0-100 chewing cycles while chewing bamboo horizontally. The upper and lower canines undergo 1 (a), 25 (b), 50 (c), 75 (d), and 100 (e) cycles of friction. The vertical lines in the middle of the bamboo represent joints.

[0032] Figure 6 A diagram showing the process of canine teeth chewing bamboo longitudinally through 0-100 chewing cycles. The upper and lower canine teeth undergo 1 (a), 25 (b), 50 (c), 75 (d), and 100 (e) chewing cycles. The vertical lines in the middle of the bamboo represent bamboo joints.

[0033] Figure 7 Illustration of the premolars undergoing 0-100 chewing cycles while chewing bamboo horizontally. The upper and lower premolars undergo 1 (a), 25 (b), 50 (c), 75 (d), and 100 (e) chewing cycles. The vertical lines in the middle of the bamboo represent nodes.

[0034] Figure 8 Illustration of the premolars chewing bamboo longitudinally through 0-100 chewing cycles. The upper and lower premolars undergo 1 (a), 25 (b), 50 (c), 75 (d), and 100 (e) chewing cycles. The vertical lines in the middle of the bamboo represent nodes.

[0035] Figure 9 Illustration of molars undergoing 0-100 chewing cycles while chewing bamboo horizontally. The upper and lower molars undergo 1 (a), 25 (b), 50 (c), 75 (d), and 100 (e) chewing cycles. The vertical lines in the middle of the bamboo represent joints.

[0036] Figure 10Illustration of molars chewing bamboo longitudinally through 0-100 chewing cycles. The upper and lower molars undergo 1 (a), 25 (b), 50 (c), 75 (d), and 100 (e) chewing cycles. The vertical lines in the middle of the bamboo represent joints.

[0037] Figure 11 These are the wear curves of canines, premolars, and molars at different chewing cycle times.

[0038] Figure 12 is the peak stress of the tooth with different post-core crown materials (10 7 Pa). DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] Example 1: Force analysis experiment on giant panda canines, premolars, and molars.

[0041] According to the study of giant panda tooth morphology, the incisor function of giant pandas gradually degenerates, so this paper only studies the stress peak and stress distribution of giant panda canines, premolars and molars to provide a reference for the restoration of giant panda dental pulp. The three types of giant panda teeth were CT scanned and imaged and imported into the modeling software Mimics, Geomagic Wrap, and SolidWorks for modeling and assembly. After that, the analysis software Ansys Workbench 2020 R2 was imported for finite element analysis to obtain the stress peak and stress cloud map of different teeth, study the stress distribution of different giant panda teeth, and provide a basic model for subsequent experiments.

[0042] Subject: With approval from the China Conservation and Protection Center for the Giant Panda, serial cross-sectional images of the giant panda's skull were obtained via CT scan during a routine physical examination. The subject of this study was an 18-year-old adult male giant panda. Giant pandas primarily use their canines, premolars, and molars to chew bamboo, and the mechanics of chewing bamboo were analyzed for these three types of teeth.

[0043] The experimental method is as follows: 1.1. 3D CT Image Production: Conventional scans of the giant panda skull were performed using a 32-slice spiral CT machine. Scanning parameters were: tube voltage 120 kV, tube current 250 mA, slice thickness 3 mm, tube rotation time 1.00 s, pitch 0.6250, reconstruction matrix 512 × 512, slice thickness 1 mm, bone window reconstruction algorithm window width 2600 HU, window level 800 HU, soft tissue window algorithm window width 300 HU, window level 40 HU. After completion of the CT scan, continuous cross-sectional images were obtained in DICOM format.

[0044] 1.2 Image Acquisition: Continuous cross-sectional images in DICOM format were read into Mimics 20.0 software. After positioning images, tissue images, and interpolation processing, each layer of image was subjected to edge segmentation, selective editing, and noise removal to remove redundant data, thus obtaining CT images of giant panda teeth.

[0045] 1.3. Tooth Selection: Three-dimensional simulations were performed on the giant panda's mandibular left canine (1C), mandibular left second premolar (2P), and mandibular left second molar (2M). Because the giant panda's first premolar is relatively short, the upper and lower first premolars cannot touch each other, and the third and fourth premolars tend to be more abrasive, resulting in significant tooth wear. Therefore, the representative second premolar was selected for this experiment. Since the first molar rubs against the fourth premolar during chewing, and the mandibular third molar has no corresponding maxillary third molar to rub against, the middle second molar was selected for this experiment.

[0046] 1.4. Threshold Selection: Refer to the tooth threshold ranges in previous finite element analysis literature and adjust the threshold range to 1200. After the threshold is selected, mimics will identify the area within the range. Use the "measure" command within mimics to measure the tooth length, and then use the "Editmasks" command to edit the mask pixels.

[0047] 1.5. Region Growing: Perform region growing operations on the edited mask. Use the "Regiongrowing" command to select the edited mask area and generate a structure independent of other areas to facilitate subsequent model generation.

[0048] 1.6. Model Generation: After completing the above steps, select the prepared mask and perform 3D model calculations. Use the "CalculatePart" command on the region-grown mask to generate a preliminary tooth model. Note that to ensure accurate finite element calculation results, select "Optimal" for the generated model quality.

[0049] After the model is initially generated, bumps or depressions will inevitably appear on its surface. Therefore, the surface of the model needs to be smoothed in 3-matic. Right-click the generated model and select "remesh" to enter the 3-matic module embedded in mimics. The main commands used here are "wrap" and "smooth". The "wrap" command is used once; the "smooth" command has a smoothing factor of 0.3 and is used three times. The model is then exported in STL file format for subsequent processing. In this experiment, the canine (1C), mandibular second premolar (2P), and mandibular second molar (2M) of the giant panda were used to generate a canine model, a premolar model, and a molar model.

[0050] 1.2.7 Surface Optimization: Although the tooth model has been optimized for smooth surfaces, the large sharp corners on the surface do not meet the quality requirements for finite element analysis. Therefore, Geomagic Studio is required for more professional surface optimization. Geomagic Studio, developed by Raindrop in the United States, is reverse engineering and 3D inspection software that can detect surface structures and perform error analysis. The main steps are: Mesh Doctor >> Convert to Points >> Encapsulate >> Accurate Surface >> Fit Surface >> Export Model.

[0051] After importing the model into Geomagic, I first entered the polygon stage, using the Mesh Doctor to repair surface defects such as spikes and small holes. I then converted the polygonal model into a point cloud. Using the Unify command with default parameters, I reduced the number of points on the surface and then encapsulated it. Then, I entered the Precise Surface module, working in Precise Surface, Editing Contours, Constructing Patches, and Constructing Grids. Finally, I clicked Generate NURBS Precise Surface and exported the model in IGES format.

[0052] 1.2.8. Element and Node Division: A tooth is a continuous geometric solid. The process of dividing its surface into multiple small elements is called discretization. The connecting points or faces are called nodes. Currently, there are many commonly used element types, such as tetrahedral elements and hexahedral elements. This experiment uses tetrahedral elements for meshing. The element and node numbers for each model are shown in Table 1.

[0053] Table 1 Number of nodes and elements in the three tooth models

[0054] 1.2.9. Model Solidification: The model generated by Geomagic is still a surface model, with a hollow interior. Therefore, you need to import the model into SolidWorks to fill in the internal structure. After completing all the above steps, you will obtain a tooth model suitable for finite element analysis.

[0055] The material properties of teeth are inherently non-uniform, but to simplify the tooth model and improve computational efficiency, teeth are typically assumed to be linearly elastic and isotropic in finite element analysis. The tooth material parameters are shown in Table 2.

[0056] Table 2 Mechanical properties of tooth materials

[0057] 1.2.10. Bite Force: The bite force borne by giant panda teeth primarily comes from the movement of the masticatory muscles when biting and chewing bamboo. According to relevant literature, giant panda bite force increases with age, reaching its peak in adulthood and decreasing in old age. Juveniles are 8 to 18 months old, subadults are 1.6 to 5.5 years old, adults are 5.6 to 20 years old, and seniors are over 20 years old. Gender differences in bite force occur between 13 and 18 months of age, with no significant differences observed in other age groups. According to measurements by researchers, the theoretical maximum bite force of adult giant pandas is 1030 N for canines, 1142 N for second premolars, and 2005 N for second molars. Based on these research findings, the vertical bite force applied to the three giant panda teeth is set to 1030 N for canines, 1142 N for premolars, and 2005 N for molars, with the direction perpendicular to the mandibular mass and in a downward direction.

[0058] 1.2.11 Analysis of the forces acting on teeth when chewing bamboo: Finite element analysis was performed using the analysis software Ansys Workbench 2020 R2 to analyze the peak Von Mises stress and Von Mises stress cloud diagram of the canine, premolar, and molar models when simulating bamboo chewing.

[0059] Here are the results: Force analysis of canine teeth: Figure 2 When chewing bamboo, the giant panda canine bite force at the vertical canine tip is 1030N, and the peak stress of the tooth is measured to be 1.0325×10 8 Pa. The stress analysis cloud diagram shows that the peak stress of the teeth is concentrated on the buccal side of the cusp, manifesting as a high stress zone forming on the cusp surface and then weakening downward from the cusp. Stress is higher in the labial area than in the lingual area. When canines are subjected to stress, the high stress area is more concentrated.

[0060] Force analysis of premolars: Figure 3 When chewing bamboo, the giant panda's bite force perpendicular to the second premolar of the mandible is 1142N, and the peak stress of the tooth is measured to be 1.1439×10 8Peak stress on teeth is concentrated on the buccal side of the occlusal tooth cusp, forming a high-stress zone there. This zone then diffuses and weakens from the occlusal area. When premolars are subjected to stress, the high-stress zone is concentrated at the cervical region.

[0061] Force analysis of molars: Figure 4 When chewing bamboo, the giant panda's bite force perpendicular to the second molar of the mandible is 2005N, and the peak stress of the tooth is 5.0511×10 7 The peak stress of the tooth is mostly concentrated in the central fossa, which then diffuses and weakens from the central fossa to the surrounding areas. When a molar is subjected to force, the high stress area of ​​the tooth is relatively dispersed.

[0062] In summary, through the three-dimensional reconstruction of the giant panda's canines, premolars, and molars and the analysis of their occlusal stress, it was calculated that the peak stress of the giant panda's canines when chewing bamboo is 1.0325×10 8 Pa, maximum stress is 10325N / cm 2 The peak stress of the second premolar is 1.1439×10 8 Pa, maximum stress is 11439N / cm 2 The peak stress of the second molar is 5.0511×10 7 Pa, the maximum stress is 5051.1N / cm 2 Understanding the stress peak and stress distribution area of ​​healthy giant panda teeth will lay the foundation for subsequent stress analysis of different post-core crown materials for giant panda teeth.

[0063] In this experiment, simple 3D models of giant panda teeth—canines, premolars, and molars—were constructed and then analyzed using finite element software. The results showed that the maximum peak stress in the enamel of all three teeth was less than the elastic modulus of giant panda enamel.

[0064] The method of the present invention is used to establish a three-dimensional model of giant panda teeth, which has the following advantages: (1) The required equipment and technology are relatively simple, data acquisition is easy to implement, and the operability is strong. CT can directly scan the research object and then output the scan results in digital form. The error is relatively small. The entire process only takes 20 to 30 minutes, which can greatly simplify the reconstruction steps and process and improve reconstruction efficiency.

[0065] (2) The data provided by the reconstructed model is comprehensive, accurate and highly reliable. The internal and external structures of giant panda teeth are complex, and the number of ex vivo teeth is extremely rare. Most of the teeth available for study are encased in hard jaw specimens. Previous studies on giant panda teeth were limited to relatively basic methods such as general measurement, data statistics, and periapical observation. They were unable to provide data information on the internal structure of the teeth and could not fully and three-dimensionally reflect the anatomical information of giant panda teeth. Because CT thin-layer scanning technology has the advantages of accurate positioning, accurate reproduction of complex and subtle structures, and accurate and reusable scanning data. Using professional modeling software MIMICS to process CT scan image data, the constructed model is adjustable and accurate to the point, which can greatly reduce the loss of original specimen data. Using spiral CT scan images of teeth, combined with professional image generation and editing software, the three-dimensional reconstruction technology has high reliability. Similarly, using giant panda tooth scan images, combined with MIMICS image generation and editing software, the giant panda tooth model reconstructed can reflect the complex structural morphology of the actual tooth surface. This method is of great significance for the reconstruction of complex tissue morphology such as the occlusal surface and pulp cavity of giant panda teeth.

[0066] (3) It does not damage the tooth specimens, the specimens have a short life cycle, low cost, and high feasibility. The grinding method is time-consuming, damages the tooth specimens, is complex to operate, and the original data is easily lost. Obviously, this reconstruction method is not suitable for the study of giant panda tooth morphology; although laser scanning can meet the accuracy requirements, it has a scanning blind spot and cannot scan and model the internal pulp cavity structure, so the reconstruction range is limited. In addition, the cost of laser scanning equipment is high, so laser scanning cannot be widely used. Using CT to scan giant panda teeth, different densities can be scanned according to different requirements. For key research areas, small-pitch thin-layer scanning can be used, while non-key areas can be scanned with wider spacing to simplify the operation. After a CT scan of the same tooth specimen, the software can be used to repeatedly model the specimen, reducing the number of times the specimen is used and reducing the cost of specimen use.

[0067] Example 2: Wear analysis experiment on giant panda canines, premolars and molars.

[0068] The giant panda tooth wear model for this experiment was created in Processing software. Using Java, the model modeled the chewing wear of the panda's canines, premolars, and molars while the panda was chewing bamboo vertically and horizontally. This tooth wear model allowed us to characterize the changes in tooth morphology as the teeth continued to chew.

[0069] The experimental method is as follows: 2.1. Program settings, including object properties, initialization settings, tooth rendering, tooth chewing trajectory and parameter display, etc.

[0070] (1) Object properties: including the width, hardness, and uniform wear resistance of teeth and bamboo.

[0071] (2) Initialization settings: including the initial positions of teeth and bamboo, and the initial wear is 0.

[0072] (3) Rendering teeth: Contains the wear logic and wear visualization of teeth, and random damage values.

[0073] (4) Tooth chewing trajectory: includes the movement of teeth as they chew, the change of the occlusal contact position of the teeth as the shape of the occlusal surface changes, the chewing direction of the teeth and random parameters.

[0074] (5) Parameter display: including the number of tooth chewing cycles and the number of pixel layers that have been rubbed.

[0075] 2.2. Giant panda tooth morphology settings: In the simulated friction test, the canines and molars were set to be the same size and symmetrically occluded. The premolars were set to have different widths, with the upper premolars larger than the lower premolars, indicating a misaligned bite.

[0076] The simulated tooth width ratio is set based on the ratio of the crown width of upper teeth to lower teeth calculated by previous researchers, see Table 3. In the two-dimensional view, an upper tooth and a lower tooth are represented as an irregular matrix of a defined number of pixels. Canine teeth have rounded cusps. The width of the upper and lower premolars is different. The upper premolar is larger than the lower premolar, with a malocclusion, and the premolars have three rounded cusps. Because the upper and lower premolars are asymmetrically arranged, the maxillary third premolar and the mandibular second premolar are used for friction. The molars are characterized by high cusps on both sides and a low central fossa. The experimental simulation is carried out in two-dimensional space, and the observation angle of the tooth model in this experiment is on the labial side of the teeth.

[0077] Research by relevant scholars indicates that giant pandas favor the cold-arrow bamboo species, which ranges in diameter from 3 to 25 mm. This experiment selected bamboo with a diameter of 15 mm within this range, with a simulated diameter of 150 pixels. The bamboo does not require a specific height setting, as its height does not affect tooth wear during feeding.

[0078] Table 3 Tooth width and height settings

[0079] 2.3. Giant panda chewing cycle setting: Assume that the giant panda's chewing cycle is divided into three stages: Opening stroke: The mandible opens and moves laterally to the equilibrium side. When further opened, the mandible swings laterally and backwards to the medial plane.

[0080] Closing stroke: As the mandible moves to the side toward the chewing side, the jaw closes until the buccal sides of the lower teeth are in line with the upper teeth.

[0081] During the friction stroke, the mandible moves lingually and backward toward the symmetrical position, while the chewing surfaces of the upper and lower teeth slide against each other, grinding the food between them. The friction stroke ends near the end point of the symmetrical position, and the next chewing cycle begins with the subsequent opening stroke.

[0082] 2.4. Giant panda chewing direction setting: Assuming that the giant panda chews clockwise, in order to be more realistic, a random parameter 30 is added to the giant panda's chewing cycle, which can intersperse counterclockwise chewing cycles with clockwise chewing cycles. The giant panda will chew counterclockwise once every three clockwise chewing cycles.

[0083] 2.5. Tooth Material Settings: Uniform wear resistance was achieved for the tooth structure. A layer of durable enamel was added to the occlusal contact surface. Based on the program hardness of 70 set by Tomas for horse teeth, the simulated hardness of the giant panda's enamel was set to 86, and the dentin to 17.6, using a 4:1 ratio of real hardness to simulated hardness.

[0084] Table 4 Tooth material property settings

[0085] 2.6 Wear logic settings: "Tooth wear" refers to the material loss caused by friction and mechanical wear. Following the basic principles of contact mechanics, the present invention applies the following assumptions:

[0086] Assuming the volume loss due to wear V abr and wear distance S abr and friction force F abr Proportional (Reye-Akkad-Khrushchev wear law): ; (1) During the friction stroke, the teeth move on each pixel, causing the pixels to gradually wear out until the lower teeth reach the starting point of the opening stroke; (2) With each step, the damage from friction will accumulate, and when the pixel damage value exceeds the defined maximum damage value, it will be erased. The maximum damage value is the simulated hardness pixel storage value set in the previous step;

[0087] (3) When a pixel is erased, the next undamaged pixel below becomes part of the new occlusal surface; (4) Once this particular pixel comes into contact with the corresponding pixel, the damage to that pixel will rise again until that pixel also exceeds the maximum damage and is erased; (5) Repeatedly, the loss of tooth structure forms a new shape of the occlusal surface; Preferably, a random value between 0 and 2, such as 0.5, is added to the pixel damage value to simulate the 0.5% probability of random damage caused by stones or other factors during daily eating.

[0088] 2.7 Wear visualization settings: A simulation run was created by repeatedly executing the chewing cycle. In the simulation run, the damage on the pixel surface is represented by a color ranging from green (low damage) to red (high damage).

[0089] The occlusal surface of the tooth is colored using a rendering method. During tooth movement, the rendered object is moved to the center of the canvas using friction. The color values ​​of the occlusal surface vary between 0 and 255, with damage colors ranging from green to red. The color values ​​define the color of the occlusal surface, and the tooth body is formed by a one-pixel-wide curve. The yellow line surrounding the tooth body is a realistic visualization.

[0090] During the simulation, the tooth size is reduced as each pixel is worn away by the rendering process. When the model is running, the worn pixel color changes on the occlusal surface of the tooth.

[0091] Through the above steps, damage visualization is achieved. Because a single pixel is difficult to see, a three-pixel line is set simultaneously. The other two pixel lines do not participate in the wear and do not affect the tooth wear count. The color is set by the stroke (a color range of 0-255), with each step increasing red and decreasing green.

[0092] 2.8. Add canvas parameter display: Add a chewing cycle count display and a display of the number of worn pixel layers of the upper and lower teeth on the canvas as the chewing cycle progresses, providing results that can quantify the degree of wear for subsequent data analysis.

[0093] Friction model of canine teeth: Figure 5-Figure 6 The simulation shows the canine teeth chewing bamboo horizontally and vertically through 0-100 chewing cycles. The simulation shows that after 75 chewing cycles, a wear plateau becomes visible on the occlusal surface in the positive direction for horizontal chewing, with 1806 layers (approximately 36.12 pixels) worn. After 100 chewing cycles, the wear plateau reaches 2284 layers (approximately 45.68 pixels), and this wear increases with further simulations. For vertical chewing, wear becomes visible on the occlusal surface in the positive direction after 100 chewing cycles, with 1838 layers (approximately 36.76 pixels) worn, and this wear increases with further simulations.

[0094] Friction model of premolars: Figure 7-Figure 8Figure 1 shows the process of premolars chewing bamboo horizontally and vertically through 0-100 chewing cycles. Simulations of premolars chewing bamboo vertically show visible cusp wear after 50 cycles, reduced groove depth, and 1083 friction layers (approximately 21.66 pixels). After 100 chewing cycles, the number of worn layers reached 1712 (approximately 34.24 pixels), with further simulations showing a decrease in cusp wear and a shallower groove depth. Simulations of premolars chewing bamboo horizontally show visible cusp wear after 100 chewing cycles, reduced groove depth, and 514 worn layers (approximately 10.28 pixels), which further increases with subsequent wear.

[0095] Friction model of molars: Figure 9-10 This image shows the process of molars chewing bamboo horizontally and vertically through 0-100 chewing cycles. The simulation of the molar chewing bamboo vertically shows that after 50 cycles, the depth of the molar's central fossa becomes visibly shallower, with 1048 worn pixels (approximately 20.96 pixels) worn away. By the 100th chewing cycle, the depth of the molar's central fossa becomes further shallower, with 2576 worn pixels (approximately 51.52 pixels) worn away. The depth of the molar's central fossa continues to shallower as the simulation progresses. The simulation of the molar chewing bamboo horizontally shows that after 50 cycles, the depth of the molar's central fossa becomes visibly shallower, with 800 worn pixels (approximately 16 pixels) worn away. By the 100th chewing cycle, the depth of the molar's central fossa becomes further shallower, with 1970 worn pixels (approximately 39.4 pixels) worn away. The depth of the molar's central fossa continues to shallower as the simulation progresses.

[0096] The wear results of canines, premolars and molars at different chewing cycle times are shown in Table 5.

[0097] Table 5 Wear of canines, premolars and molars at different chewing cycles

[0098] Figure 11It can be seen that when giant pandas chew bamboo horizontally, the crowns of canines are completely worn out after 459 friction cycles, the crowns of premolars are completely worn out after 327 friction cycles, and the crowns of molars are completely worn out after 282 cycles. When giant pandas chew bamboo vertically, the crowns of canines are completely worn out after 535 cycles, the crowns of premolars are completely worn out after 179 friction cycles, and the crowns of molars are completely worn out after 220 cycles. When chewing bamboo horizontally, with the same number of chewing cycles, the wear of canines, premolars, and molars is ranked as follows: canines > molars > premolars. When chewing bamboo vertically, with the same number of chewing cycles, the wear of canines, premolars, and molars in the first half of the chewing process is ranked as follows: premolars > molars > canines. In the second half of the chewing process, the wear of molars > canines > premolars. Comparing the same teeth chewing bamboo in different postures, the wear of canines when chewing bamboo horizontally is greater than that when chewing bamboo vertically. The wear of premolars and molars is greater when chewing bamboo vertically.

[0099] The equivalence between chewing cycles and actual wear time: When a molar chews 206 times, the proto-cusp and anterior cusp of the molar's occlusal surface wear into a single plane. Based on the conclusions drawn by Wei Fuwen in his research on giant panda age determination, the age range of a giant panda can be determined by the degree of molar wear. When the molar cusps merge into a single plane, the giant panda's age range is 20-26 years old. The chewing cycle at which the molar cusps just merge into a single plane is 206, so at 206 chewing cycles, the giant panda's age is approximately 23 years old. According to Sun Mengmeng's research, giant pandas complete the transition from deciduous teeth to transverse teeth at 18 months of age. Because the teeth in this experiment were initially healthy and had no wear, the number of cycles in the experiment began at the age of one and a half, and at 206 cycles, the panda would be 23 years old. Therefore, one cycle of wear is equivalent to approximately 38 days of wear in a giant panda.

[0100] .

[0101] Based on the equivalence between wear cycles and actual wear time, one cycle of wear is equivalent to approximately 38 days of wear for a giant panda. The number of cycles required for complete wear of the crowns of a giant panda's canines, premolars, and molars is 459, 179, and 220, respectively. It can be estimated that after a giant panda completes the transition from deciduous teeth to transverse teeth and is not exposed to external forces, it will take approximately 47 years, 19 years, and 23 years for the crowns of its canines, premolars, and molars to completely wear out, respectively.

[0102] In summary, canine teeth wear faster when chewing bamboo horizontally than when chewing bamboo vertically. Premolars and molars wear slower when chewing bamboo horizontally than when chewing bamboo vertically. When chewing bamboo in the same direction, molars wear faster than canines and premolars. In a simulated giant panda chewing bamboo diet, complete wear of canine, premolar, and molar crowns would take approximately 47, 19, and 23 years, respectively.

[0103] Compared with real canines after wear, the tip of the canine in the model of the present invention will also generate a wear platform similar to the top of the real tooth after simulated wear from chewing bamboo, which verifies the feasibility of the giant panda canine wear model. In the tooth model after simulated wear of premolars, the height difference between the cusp and the groove of the maxillary premolar will decrease after wear, and the multiple cusps of the premolar will fuse due to wear, while the wear morphology of real premolars will show similar wear morphology, which verifies the feasibility of the premolar wear model. Compared with real molars after wear, the depth of the central fossa of the simulated molars becomes shallower and the cusps are gradually flattened after chewing bamboo. Real molars will also show similar wear morphology changes after chewing bamboo. This verifies the feasibility of our molar wear model.

[0104] The present invention constructs a wear model to test the wear resistance of giant panda teeth, which has the following advantages: (1) Avoided destructive research on giant panda teeth.

[0105] (2) This experiment simulates the chewing movement of giant panda teeth and the changes in tooth morphology after tooth wear. The results are richer. It can not only evaluate the wear resistance of different teeth, but also determine the parts of the teeth that are prone to wear, so as to carry out preventive repairs in advance for these parts of the giant panda.

[0106] (3) Wear can be visualized. Through different color changes, the evolution of the wear appearance of the giant panda's upper and lower teeth can be directly observed.

[0107] (4) To better simulate the chewing motion of giant pandas, this experiment added a random loop to the chewing cycle to simulate the giant panda's unconscious random chewing behavior when eating. Compared with the horse tooth wear model developed by Tomas, this experiment added a visualization of the number of friction layers, which can quantify the amount of tooth wear, making the comparison before and after wear more intuitive.

[0108] Example 3: Giant panda dental pulp restoration technology.

[0109] Referring to the method of implementation 1, a stress analysis of panda canines, premolars, and molars with different post and core crown materials was performed: the parameters of the post and core material were input into the software through finite element analysis technology, and the stress analysis of the canines, premolars, and molars after the addition of the post and core crown was performed to compare the enamel stress peak and stress distribution of different post and core crown materials.

[0110] Referring to the method of Example 2, the wear resistance of canines, premolars, and molars wearing different crown materials was analyzed: a Java language model was used to establish canine wear models, premolar wear models, and molar wear models when wearing different crown materials, and the wear resistance of different crowns was compared.

[0111] The endodontic restoration technology of giant pandas was evaluated based on the stress and wear resistance of endodontic restoration models made of the same material.

[0112] 3.1. Mechanical analysis results of different post-core crown material combinations for canines, premolars, and molars: When chewing bamboo, the maximum bite force applied to the giant panda canine was 1030 N, perpendicular to the canine cusp. The stress peak was concentrated on the buccal side of the cusp. The stress distribution pattern was similar for both the fiber post-core crown group and the zirconia post-core crown group, starting from the cusp and then spreading downward and weakening. A high-stress zone formed on the cusp surface, with higher stress on the labial side than on the lingual side.

[0113] When chewing bamboo, the pandas applied a maximum bite force of 1142 N perpendicular to the premolars. The peak stress in the premolars was concentrated on the occlusal slope. The stress distribution patterns were similar in both the fiber post-core crown and zirconia post-core crown groups, with both groups exhibiting a pattern of spreading from the intercuspal groove slope to the surrounding area and then weakening. This formed a high-stress zone on the occlusal slope.

[0114] When chewing bamboo, a bite force of 2005 N was applied perpendicular to the panda's molars. Peak stress was concentrated in the central fossa. The stress distribution patterns of the molars were similar across all groups, regardless of whether they were fiber, alloy, or zirconia post-core crowns: they all diffused from the central fossa and weakened in the surrounding areas.

[0115] Table 6 Peak stress of different teeth with different post-core crown material combinations

[0116] In the canine stress analysis of different post-core crown materials, a giant panda canine bite force of 1030N was applied perpendicular to the canine cusp. The calculated stress peaks of different post-core crown materials were not much different. The highest stress peak of the zirconia post-core + all-ceramic crown was 8.1557×10 7 Pa, the lowest stress peak of fiber resin post core + zirconia crown is 8.0024×107 Pa.

[0117] In the stress analysis of premolars with different post-core crown materials, a giant panda molar bite force of 1142N was applied perpendicular to the premolar. The calculated stress peaks of different post-core materials were significantly different. The highest stress peak of the zirconia post-core + resin crown tooth was 1.9529×10 8 Pa, the lowest stress peak of the fiber resin post-core crown is 1.4396×10 8 Pa.

[0118] In the stress analysis of molars with different post and core crown materials, a 2005N bite force was applied perpendicular to the giant panda's molar. The calculated peak stress values ​​for the fiber resin post and core material were not much different from those for the zirconia post and core material. The peak stress value of the fiber resin + zirconia crown was 4.1905×10 7 Pa. The lowest peak stress of zirconia post-core crown is 3.4707×10 7 Pa.

[0119] 3.2. Wear resistance analysis results of different crowns of canines, premolars and molars: Canine teeth wearing all-ceramic and zirconia crowns were subjected to 0-100 chewing cycles while chewing bamboo horizontally. Simulations showed that the canine teeth wearing the crowns exhibited a similar appearance to the original teeth after wear. After 100 chewing cycles, the number of worn layers was 1418 (approximately 28.36 pixels). Canine teeth wearing zirconia crowns showed little wear within 100 chewing cycles, with the number of worn layers reaching 746 (approximately 14.92) at 100 chewing cycles, and this number increased with further simulations. Canine teeth wearing zirconia crowns demonstrated greater wear resistance when chewing bamboo horizontally, compared to those wearing all-ceramic crowns.

[0120] Canine teeth wearing all-ceramic and zirconia crowns were subjected to 0-100 chewing cycles while chewing bamboo in a vertical position. Simulations showed that the canine teeth wearing the crowns had a similar appearance to the original teeth after wear. The canine teeth wearing all-ceramic crowns showed slightly visible wear on the occlusal surface after 100 chewing cycles, with 1134 wear layers (approximately 22.68 pixels). The canine teeth wearing zirconia crowns had 580 wear layers (approximately 11.6 pixels) at 100 chewing cycles, and this number increased with further simulations. Canine teeth wearing zirconia crowns showed greater wear resistance than those wearing all-ceramic crowns when chewing bamboo in a vertical position.

[0121] Premolars wearing all-ceramic and zirconia crowns were subjected to 0-100 chewing cycles while chewing bamboo in a vertical position. Simulations showed that the appearance of premolars wearing crowns after wear was similar to that of the original teeth. At 100 chewing cycles, the occlusal cusps of premolars wearing all-ceramic crowns began to round, the groove depth decreased, and the number of worn layers was 1211 (approximately 24.22 pixels). At 100 chewing cycles, premolars wearing zirconia crowns showed less noticeable occlusal wear, with 671 worn layers (approximately 13.42 pixels), which increased with further simulations. Premolars wearing zirconia crowns showed greater wear resistance when chewing bamboo in a vertical position than those wearing all-ceramic crowns.

[0122] Premolars wearing all-ceramic and zirconia crowns were subjected to 0-100 chewing cycles while chewing bamboo horizontally. Simulations showed minimal wear changes over 100 cycles, but the wear resistance of the two types of teeth could be compared using the number of worn layers. At 50 chewing cycles, the premolars wearing all-ceramic crowns had 160 worn layers (approximately 3.2 pixels), while those wearing zirconia crowns had 70 worn layers (approximately 1.4 pixels). At 100 chewing cycles, the premolars wearing all-ceramic crowns had 322 worn layers (approximately 6.44 pixels), while those wearing zirconia crowns had 164 worn layers (approximately 3.28 pixels), and this number increased with further simulations. Premolars wearing zirconia crowns demonstrated greater wear resistance when chewing bamboo horizontally.

[0123] Molars wearing all-ceramic and zirconia crowns were subjected to 0-100 chewing cycles while chewing bamboo in a vertical position. Simulations showed that the appearance of the crowned molars after wear was similar to that of the original teeth. At 100 chewing cycles, the occlusal depth of the molars wearing all-ceramic crowns decreased, with 1710 wear layers (approximately 34.2 pixels) visible. At 100 chewing cycles, the molars wearing zirconia crowns showed slight wear on the occlusal surface, with 908 wear layers (approximately 18.16 pixels) visible, which increased with further simulations. Molars wearing zirconia crowns showed greater wear resistance than molars wearing all-ceramic crowns when chewing bamboo in a vertical position.

[0124] Molars wearing all-ceramic and zirconia crowns were subjected to 0-100 chewing cycles while chewing bamboo horizontally. Simulations showed that the appearance of the crowned molars after wear was similar to that of the original teeth. At 100 chewing cycles, the occlusal depth of the molars wearing all-ceramic crowns became noticeably shallower, with 1296 worn layers (approximately 25.92 pixels) worn. Molars wearing zirconia crowns showed no significant wear at 100 chewing cycles, with 706 worn layers (approximately 14.12 pixels) worn, which increased with further simulations. Molars wearing zirconia crowns demonstrated greater wear resistance when chewing bamboo horizontally.

[0125] Friction models of canines, premolars, and molars using fiber resin as crowns during horizontal and vertical bamboo chewing were used. Simulations showed that within 10 chewing cycles of chewing bamboo in the horizontal direction, canines showed significant wear, with 1952 layers of wear (approximately 39.04 pixels). Within 10 chewing cycles of chewing bamboo in the vertical direction, canines showed significant wear, with 1574 layers of wear (approximately 31.48 pixels). Within 10 chewing cycles of chewing bamboo in the vertical direction, premolars showed significant wear, with 1532 layers of wear (approximately 30.64 pixels). Within 10 chewing cycles of chewing bamboo in the horizontal direction, teeth showed significant wear, with 426 layers of wear (approximately 8.52 pixels). When chewing bamboo vertically for 10 cycles, the molars showed significant wear, with 2210 layers (approximately 44.2 pixels) worn away. When chewing bamboo horizontally for 10 cycles, the molars showed significant wear, with 1708 layers (approximately 34.16 pixels) worn away. When wearing a resin crown, the friction rate was too high. After no more than 25 cycles, the crown was completely worn away, and the program stopped friction.

[0126] Table 7 shows that when giant pandas chew bamboo horizontally, canines wearing all-ceramic and zirconia crowns completely wore out after 688 and 1488 friction cycles, respectively. Premolars wearing all-ceramic and zirconia crowns completely wore out after 490 and 1046 friction cycles, respectively. Molars wearing all-ceramic and zirconia crowns completely wore out after 423 and 911 cycles, respectively. When giant pandas chew bamboo vertically, canines wearing all-ceramic and zirconia crowns completely wore out after 802 and 1518 friction cycles, respectively. Premolars wearing all-ceramic and zirconia crowns completely wore out after 288 and 572 friction cycles, respectively. Molars wearing all-ceramic and zirconia crowns completely wore out after 330 and 715 cycles, respectively. Regardless of the posture in which the giant pandas chewed bamboo, the wear resistance of teeth wearing zirconia crowns was consistently superior to that of all-ceramic crowns.

[0127] Table 7 Number of friction cycles for complete wear of canines, premolars and molars with different crown materials

[0128] Table 8 Wear resistance index of different crowns, different teeth and native teeth

[0129] Under the same bamboo chewing occlusal contact conditions, canines, premolars, and molars wearing all-ceramic crowns had similar wear resistance indices compared to native teeth, with simulations showing the wear resistance of all-ceramic crowns to be approximately 1.53 times that of native teeth. Canines, premolars, and molars wearing zirconia crowns had similar wear resistance indices compared to native teeth, with simulations showing the wear resistance of zirconia crowns to be approximately 3.22 times that of native teeth.

[0130] In summary, fiber resin posts and cores combined with zirconia crowns are suitable for canine endodontic restorations. For premolar endodontic restorations, fiber resin posts and cores or zirconia posts and cores combined with zirconia crowns are used, depending on the intended restoration. Zirconia posts and core crowns are suitable for molar endodontic restorations. The wear resistance of different crown materials is ranked as follows: zirconia > all-ceramic > enamel > fiber resin. The wear resistance index of all-ceramic crowns is approximately 1.53 times that of native teeth, while the wear resistance index of zirconia crowns is approximately 3.22 times that of native teeth.

[0131] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for constructing a giant panda dental pulp restoration model, characterized in that: The following steps are involved: Step 1: Force analysis of panda canines, premolars, and molars fitted with different post and core crown materials, specifically including the following steps: 1) Post-core-crown assembly: constructing tooth models of giant panda canines, premolars, and molars fitted with different post-core-crown materials; 2) Loading bite force: The vertical bite force applied to the three giant panda teeth is set to a N for canines, b N for premolars, and c N for molars, with the direction set perpendicular to the mandible and downward. 3) Finite element analysis of tooth occlusion: Obtain the peak stress and stress contour of each tooth model after load application; Step 2: Establish canine, premolar, and molar wear models when wearing different crown materials, including settings for giant panda tooth morphology, giant panda chewing cycle, giant panda tooth chewing direction, tooth material, wear logic, wear visualization, and canvas parameter display. Output changes in tooth morphology as chewing progresses, and implement wear resistance analysis of canines, premolars, and molars wearing different crown materials. Step 3: Output the optimal restoration material results for the pulp and tooth of the giant panda's canines, premolars, and molars.

2. The method for constructing a giant panda dental pulp tooth restoration model according to claim 1, wherein: The tooth model construction method is as follows: CT scans are performed on canines, premolars, and molars equipped with post-core crown materials to obtain CT images of giant panda teeth; mask pixels are edited after threshold selection; and a region growing operation is performed on the edited mask. Then, the mask is used to calculate the three-dimensional model to generate a preliminary tooth model; the preliminary tooth model is subjected to surface smoothing and surface optimization in sequence; Finally, the model is solidified to obtain a three-dimensional model of the giant panda's canines, premolars and molars.

3. The method for constructing a giant panda dental pulp tooth restoration model according to claim 1, wherein: In step 1, a=1030, b=1142N, and c=2005.

4. The method for constructing a giant panda dental pulp tooth restoration model according to any one of claims 1 to 3, wherein: In step 2, the chewing cycle of the giant panda is set as follows: Assume that the chewing cycle of the giant panda is divided into three stages: Opening stroke: The mandible opens and moves laterally to the equilibrium side; when further opened, the mandible swings laterally and backwards to the mid-plane; Closing stroke: When the mandible moves to the side of the chewing side, the jaw closes until the buccal side of the lower teeth is in line with the upper teeth; Friction stroke: The mandible moves backward on the lingual side toward the symmetrical position, while the chewing sides of the upper and lower teeth slide against each other and grind the food in the middle. The friction stroke ends at the symmetrical position near the end point, and the next chewing cycle begins with the next opening stroke. The specific setting of the giant panda's teeth chewing direction is: assuming that the giant panda chews in a clockwise direction, random parameters are added to the giant panda's chewing cycle, and counterclockwise chewing cycles are interspersed in the giant panda's clockwise chewing cycle.

5. The method for constructing a giant panda dental pulp tooth restoration model according to claim 4, wherein: In step 2, the wear logic settings are as follows: Assuming the volume loss due to wear V abr and wear distance S abr and friction force F abr Proportional to: ; During the friction stroke, the teeth will move on each pixel, causing the pixels to gradually wear out until the lower teeth reach the starting point of the opening stroke; with each step, the damage of friction will accumulate, and when the pixel damage value exceeds the defined maximum damage value, it will be erased; when the pixel is erased, the next undamaged pixel below becomes part of the new occlusal surface; this process is repeated, and the loss of tooth structure forms a new shape of the occlusal surface.

6. The method for constructing a giant panda dental pulp tooth restoration model according to claim 5, wherein: In step three, the canine wear model includes the wear model of the canine chewing bamboo horizontally and the wear model of the canine chewing bamboo vertically; the premolar wear model includes the wear model of the premolar chewing bamboo horizontally and the wear model of the premolar chewing bamboo vertically; the molar wear model includes the wear model of the molar chewing bamboo horizontally and the wear model of the molar chewing bamboo vertically.

7. The method for constructing a giant panda dental pulp tooth restoration model according to claim 6, wherein: The materials for post and core crowns of canines, premolars and molars are selected from one of the following types: fiber resin post and core crown, fiber resin + zirconia crown, fiber resin + all-ceramic crown, zirconia post and core crown, zirconia post and core + all-ceramic crown, zirconia post and core + resin crown.

8. The method for constructing a giant panda dental pulp tooth restoration model according to claim 7, wherein: In step three, at least 100 chewing cycles are performed when chewing bamboo in the horizontal and vertical directions, and visual images of tooth wear and the number of wear layers under multiple chewing cycles are output respectively.

9. The method for constructing a giant panda dental pulp tooth restoration model according to claim 8, wherein: The post and core crown restoration of the pulp of canine teeth uses fiber resin post and core + zirconia crown; the post and core crown restoration of the pulp of premolars uses fiber resin post and core or zirconia post and core combined with zirconia crown; the post and core crown restoration of the pulp of molars uses zirconia post and core crown.

10. A model obtained according to the method for constructing a giant panda dental pulp and tooth restoration model according to any one of claims 1 to 9.

Images