Dental implant imitating natural tooth root curvature and design and implantation system thereof

Abstract

The invention relates to the technical field of dental implants in oral medicine, in particular to an optimal design of a geometric structure of a dental implant. According to the technical scheme, the method comprises the following steps: firstly, specifying cross section general forms of three types of implants, then, creating a natural tooth model based on multiple groups of head image data, counting the value range of the curvature radius of each type of natural teeth based on the natural tooth model, and obtaining the feature size of the implant and the corresponding optimal curvature radius thereof; according to the dental implant simulating the natural tooth root curvature and the design and implantation system thereof, the morphological characteristics of natural teeth are fully considered, the specific shape of the cross section of the upper end face of each type of implant under each feature size is determined, and finally the dental implant model is created based on the results. The oral cavity biomechanical requirement and the functional adaptability of the human body oral cavity can be better met, meanwhile, large-scale production can be achieved, and the requirement of large-scale clinical application can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of dental implant technology, in particular to an optimized design of the geometry of dental implants. BACKGROUND

[0002] Dental defects not only affect the patient's masticatory efficiency and speech function, but also can cause a series of secondary problems such as adjacent tooth tilting, occlusal relationship disorder, and alveolar bone absorption, thereby affecting the overall oral health and facial aesthetics. Compared with traditional repair solutions (removable partial dentures or fixed bridge repair, etc.), dental implant repair technology, which implants dental implants into the jaw bone and then connects the upper prosthesis, can achieve good stability and masticatory function, while avoiding damage to adjacent teeth, has become the preferred intervention strategy for dental defects.

[0003] The existing dental implants are mainly divided into two categories. One is the common commercial mainstream dental implant, which is usually a rotary column or a cone, with a circular cross-sectional shape, and a plurality of commonly used sizes are determined based on the statistical data of the jaws of a large number of volunteers to achieve mass production. The other is a non-circular cross-section implant with a natural tooth shape, such as the Chinese patent CN114848189A, which discloses a personalized customized implant with a natural tooth shape and its preparation and implant system. The implant is prepared based on the three-dimensional scanning or artificial intelligence prediction of the three-dimensional data of the opposite teeth of the missing teeth, and the dental implant is the same as or similar to the normal tooth root. The posterior dental implant is a multi-root tooth with irregular shape, and the anterior dental implant is a single-root tooth with irregular shape.

[0004] The existing two types of implants have the following defects. For the first type of commercial mainstream dental implant, its single circular cross-sectional geometry cannot meet the functional load requirements of different tooth positions, which can easily cause micromotion between the implant and the bone interface, leading to poor bone integration and affecting the long-term stability of the implant. In addition, in order to ensure that the human jaw bone and adjacent teeth are not damaged, the size of the implant must be carefully selected. Due to the circular cross-section of this type of implant, the cross-sectional size of the implant can only be the minimum value of the distance between the missing teeth and the adjacent teeth and the buccal-lingual width, resulting in insufficient bone contact area and significantly reduced anti-rotation stability. For the second type of non-circular cross-section implant with a natural tooth shape, although the natural tooth implant can highly simulate the shape and function of natural teeth, due to its customized characteristics, the production cycle is long, the cost is high, and the technical complexity is high, making it difficult to achieve mass production. SUMMARY

[0005] In view of the above defects of the prior art, the present application provides a dental implant with a root curvature similar to that of a natural tooth and a design method thereof, which fully considers the morphological characteristics of a natural tooth, can better meet the biomechanical requirements and functional adaptability of the human oral cavity, can effectively utilize the limited bone space in the edentulous area, increase the contact area with the bone tissue, and thus enhance the stability and support of the implant. Meanwhile, the design of the dental implant can also realize large-scale production and meet the needs of large-scale clinical applications.

[0006] To achieve the above-mentioned purposes, the technical solution adopted by the present application is: A design method of a dental implant with a root curvature similar to that of a natural tooth, comprising: S01, a general shape category designation step: designating the general shape of the cross section of a single-root dental implant, a double-root dental implant, and a triple-root dental implant, respectively; S02, a three-dimensional model of a natural tooth creation step: creating a natural tooth model based on head image data, wherein the natural tooth model is divided into a single-root tooth model, a double-root tooth model, and a triple-root tooth model; S03, a curvature radius value range statistics step: obtaining the upper end surface cross section of the root of a natural tooth based on the natural tooth model, and obtaining the value range of the curvature radius of each type of natural tooth based on a plurality of the upper end surface cross sections; S04, an implant feature size acquisition step: acquiring a plurality of groups of bone space size data of the root of each type of natural tooth based on oral and maxillofacial CT data, converting the bone space size data into a plurality of groups of implant size data, dividing a plurality of general categories by statistics of the implant size data, and determining the feature size of each of the general categories; S05, an implant upper end surface cross section design step: acquiring optimal curvature radius data corresponding to each feature size of each type of implant by using finite element simulation, determining the specific morphology of the upper end surface cross section of each type of implant under each feature size based on the cross section feature morphology, the feature size, and the optimal curvature radius data; S06, a dental implant model creation step: constructing an implant model based on the specific morphology of the upper end surface cross section and the feature size; and designing an implant abutment model matched with the implant model, wherein the bottom cross section specific morphology of the implant abutment model is consistent with the specific morphology of the upper end surface cross section.

[0007] Firstly, in S01 step, in order to realize the large-scale production of the implant, based on the commonness of the cross-sectional morphological characteristics of a plurality of natural tooth roots, the general shape of the cross section of each type of implant in the application is determined. Specifically, the cross-sectional curve of the single-root tooth implant is designed as an elliptical shape; the cross section of the double-root tooth implant adopts a symmetrical structure with four round corners and four recesses; and the cross section of the three-root tooth implant is designed as a symmetrical shape containing three round corners and three recesses.

[0008] Then, in S02 step, the CBCT image data of the heads of a plurality of healthy volunteers is obtained, and a medical image processing software such as Mimics is used to extract a plurality of three-dimensional models of different types of natural teeth saved in STL format for subsequent analysis. Among them, the three-dimensional models of natural teeth are divided into single-root tooth models, double-root tooth models and three-root tooth models based on the number of tooth roots of the natural teeth.

[0009] In S03 step, based on the natural tooth model established in S02 step, the upper end surface of each type of natural tooth is cut, and the value range of the curvature radius of the tooth root cross-sectional curve is counted. For single-root teeth, since the cross-sectional shape is relatively simple, only the range of curvature radius in one direction needs to be analyzed; for double-root teeth and three-root teeth, since the cross-sectional shape is more complex, the curvature change has directional differences, so the curvature radius in three dimensions of the mesial-distal direction, the buccal-lingual direction and the angle between the two is statistically analyzed, respectively, so as to obtain the value range of the curvature radius of the double-root tooth and the three-root tooth in three different directions.

[0010] Further, in the S04 step, the key feature sizes of the implant are obtained. First, based on the oral and maxillofacial CT data of a plurality of healthy volunteers, a three-dimensional maxillofacial model is constructed using medical image processing software. On this basis, a plurality of size parameters of the alveolar bone space corresponding to each type of natural tooth are extracted, and each set of bone space size data includes key parameters such as interproximal distance, buccal-lingual width, and jaw bone height. Subsequently, the above bone space size data is converted into corresponding implant size parameters, and each set of implant size data includes mesial-distal direction diameter, buccal-lingual diameter, and implant length of the cross section of the upper end. Specifically, the conversion can be performed by referring to the design standards of conventional implants, for example, the ideal distance between the implant center and the proximal interproximal side of the natural tooth is calculated by the formula: D (distance between implant center and proximal interproximal side of natural tooth) = R (radius of implant) + 2 mm, to obtain the mesial-distal direction diameter of the implant, and the bone wall of 0.5 mm around the implant is reserved, and the buccal-lingual diameter of the implant should be at least 1 mm less than the original buccal-lingual bone width (0.5 mm on both sides). In terms of implant length, considering the existence of important anatomical structures such as maxillary sinus, nasal floor and mandibular canal at the bottom of the maxilla and mandible, in order to avoid damaging nerves and blood vessels and ensure safety, according to the implant design standard, the root end of the implant should maintain a safety distance of at least 1 mm from the above structures, thereby determining its length.

[0011] Then, a plurality of sets of implant size data for each type of implant are statistically analyzed, and a plurality of general categories are divided, and the feature sizes of each general category are determined, for example, after obtaining a plurality of sets of implant size data for single tooth, the size distribution can be used to divide them into three general categories of large, medium and small, and then the most common representative size is selected from the plurality of sets of implant size data of each general category as the feature size of the single tooth implant, and each feature size includes mesial-distal direction diameter, buccal-lingual diameter, and implant length. Thus, for single tooth implants, three representative size specifications can be mass-produced, thereby realizing standardized and classified design of implant size, and the specific size grouping can be determined in combination with actual conditions.

[0012] Further, in the S05 step, for each type of dental implant, the specific form of the upper end surface cross section is optimized according to its corresponding characteristic size. In the S02 step, although the range of the curvature radius of each type of implant has been obtained through the root cross section analysis, this range is still insufficient to directly determine the optimal curvature parameter of the implant under different size conditions. Therefore, the present application uses the finite element simulation method to obtain the optimal curvature radius data matched with each characteristic size. Specifically, for each characteristic size of each type of implant, a plurality of simulation models are constructed. Each model maintains the unified general form and size parameters of the implant, and only changes the value of the curvature radius, so as to compare the influence of different curvatures on the biomechanical performance of the implant under the same boundary conditions. In the finite element analysis process, the stress state of the human natural tooth in the mastication process is simulated: 100 N vertical load and 100 N lateral force in the 45° direction are respectively applied at the crown position to reproduce the combined stress conditions that may be encountered in the actual mastication process. Through simulation calculation, the stress peak value and stress distribution cloud diagram in the jaw bone are obtained, and then the mechanical performance of the implant under different curvature radii is evaluated, and the optimal curvature radius under the corresponding characteristic size is determined accordingly. Then, the general form of the cross section, the characteristic size and the optimal curvature radius data are comprehensively considered to determine the specific form of the upper end surface cross section of each type of implant under each characteristic size.

[0013] Finally, in the S06 step, by inputting the specific form of the upper end surface cross section and the length of the implant with the corresponding characteristic size, a three-dimensional model of each type of implant under each characteristic size is constructed using three-dimensional software such as SOLIDWORKS, and the implant abutment model matched with each type of dental implant under multiple characteristic sizes is also designed, wherein the cross section form of the bottom of the implant abutment and the connecting end surface of the implant is consistent with the specific form of the corresponding dental implant end cross section, realizing the accurate matching and stable connection of the two in structure, so as to form a dental implant design system covering multiple types and multiple size specifications.

[0014] The application specifies the general shape of the cross section of different types of implants, and obtains the numerical range of all curvature radii of the cross section curve of different types of implants based on the natural tooth model, as the basis for the design of different types of implant cross sections in the application, so that the cross section shape of each type of implant in the application can highly fit the root cross section shape of the corresponding natural tooth, instead of the conventional circular cross section, significantly improving the adaptability and stability of the implant and the oral environment of the human body; in addition, unlike the existing natural tooth implant which is usually based on individual tooth morphology for one-to-one replication and is difficult to realize standardized and large-scale production, the application specifies the implant cross section general shape that fits the natural tooth morphology for natural teeth belonging to the same category (such as single-root teeth, double-root teeth or triple-root teeth), and sets the characteristic size of each type of implant for large-scale production, and determines the corresponding curvature parameters in combination with the optimization of biomechanical properties, so that the large-scale and standardized design of the same type of tooth implant can be realized. Through the above design method, the application not only retains the bionic adaptability of the implant to the natural tooth morphology, but also realizes the coverage of multiple size specifications under each type, meeting different clinical needs.

[0015] As preferred, the step S02 and the step S03 further comprise a natural tooth three-dimensional model optimization step, in which the tooth surface defects of the natural tooth model are optimized and removed.

[0016] Since the human dentition is closely arranged, and the natural tooth root is closely connected with the alveolar bone, the natural tooth model extracted by using medical image processing software such as Mimics in step S02 has many defects, so the created natural tooth model needs to be further imported into Geomagic Wrap to remove the tooth surface defects of the target tooth site by using the feature removal and rapid fairing functions to improve the model quality and save it as an STL model.

[0017] As preferred, the step S02 and the step S04 further comprise a Gaussian curvature analysis and longitudinal cross-sectional curvature analysis step, the Gaussian curvature analysis is performed based on the natural tooth model to obtain the root surface characteristics of each type of natural tooth; the longitudinal cross sections of the mesial and distal directions of the natural tooth root are obtained, and the longitudinal curvature characteristics of each type of natural tooth are obtained based on the analysis of a plurality of longitudinal cross sections; the step S06 further comprises an implant root shape optimization step; the implant root shape is optimized based on the longitudinal curvature characteristics, and the Gaussian curvature of the implant is adjusted to conform to the surface characteristics.

[0018] Gauss curvature, as an intrinsic geometric feature of a surface, can comprehensively reflect the coupling relationship between the two principal curvatures of the root surface of a tooth. Compared with the analysis method of single cross-sectional curvature, Gauss curvature can reveal the biomechanical nature of the natural tooth root in the stress process. Based on this characteristic, the natural tooth three-dimensional model established by the application is imported into Geomagic Wrap software, the non-uniform rational B-spline surface is constructed by using the precise surface modeling function thereof, and finally saved as an entity model in IGES format. Then the model is imported into Rhino software, and the Gauss curvature distribution image of the root surface is obtained through the built-in surface curvature analysis tool thereof. The root surface characteristics of each type of natural tooth are analyzed. Specifically, for single-root teeth, the Gauss curvature of the root end region is greater than zero, indicating that the region presents a spherical curved feature; and the Gauss curvature of the remaining most regions is zero, showing a flat structure such as a cylindrical surface or a plane. The root morphology of double-root teeth and triple-root teeth is more complex: the pulp bottom region presents negative Gauss curvature, showing a saddle-shaped hyperboloid feature; the root tip part still presents positive Gauss curvature, that is, a spherical curved shape; in addition, the regions are mostly zero curvature regions, that is, flat structures.

[0019] The above results show that in the implant root shape design process, the surface characteristics of different regions should be fully considered, especially the differentiated design of the middle and root tip parts. For this purpose, the application further intercepts the longitudinal section of the natural tooth root in the mesial-distal direction to analyze the longitudinal curvature characteristics, and it is found that the longitudinal section curvature of the roots of the three types of natural teeth presents the characteristics of curve second-order continuity as a whole, that is, from the middle to the root tip, the curvature changes smoothly without mutation, and the root tip region maintains positive curvature.

[0020] Based on the above root surface characteristics and root longitudinal curvature characteristics, in the implant root shape optimization step, the implant root is designed to present a second-order continuous smooth transition curve from the middle to the root tip, and a positive curvature feature is introduced in the root tip region to simulate the spherical curved feature of the end of the natural tooth root, so as to realize the stress distribution and bone integration effect more in line with the biomechanical characteristics.

[0021] As preferred, the step S02 and the step S04 further comprise a principal curvature analysis step, the principal curvature value range of the root of each type of natural tooth is obtained based on the natural tooth model; and the step S06 further comprises an implant curvature regulation step, so that the principal curvature of the implant model conforms to the principal curvature value range.

[0022] The principal curvatures are the core parameters for describing the geometry of the root surface, which can reflect the maximum and minimum bending degree and the direction distribution of the curved surface at a certain point, thereby revealing the local mechanical transmission characteristics of the root surface. The principal curvatures of different types of natural teeth in different regions (such as the middle and root) can be obtained through principal curvature analysis, and on this basis, the curvature of the implant is regulated, and the control point of the implant surface is optimized, so that the principal curvature distribution is closer to the biomechanical characteristics of the natural tooth root, thereby improving the adaptability and long-term stability of the implant and the surrounding bone tissue.

[0023] As preferred, after the S06 step, an implant draft degree optimization design step is further included, in which the side wall inclination angle of the implant model is adjusted based on the natural tooth root morphology.

[0024] The draft degree refers to a small inclination angle set on the structural side wall during three-dimensional modeling and manufacturing to facilitate demolding and improve processing efficiency. Research has found that the natural tooth root is not completely perpendicular to the alveolar bone, but has a natural inclination trend of about 5°, which has a draft degree characteristic. Based on this physiological basis, the implant model is subjected to draft degree optimization design after the S06 step, and the side wall inclination angle of the implant model is adjusted to make it closer to the natural tooth root morphology, thereby optimizing the stress distribution, reducing local stress concentration, enhancing the bone integration effect, and improving the manufacturing process and clinical adaptability.

[0025] As preferred, after the S06 step, a dental implant model optimization step is further included, in which the side wall inclination angle of the mating part of the implant model and the implant abutment model is adjusted.

[0026] Based on the structural characteristics of the connection area between the implant and the implant abutment, the present application sets the Morse taper at the mating part of the implant abutment and the implant to 5.7° to improve the anti-rotation ability of the implant abutment. The Morse taper refers to a self-locking connection structure formed by the close fit of the conical surface and the conical surface between two mating parts. In the present application, the Morse taper is specifically defined as the included angle between the vertical central axis of the implant abutment connection part and the extension direction of its side wall being 5.7°. This design enables the implant abutment to form a self-locking fastening effect with the implant when subjected to axial pressure, thereby significantly improving the stability and sealing of the connection, optimizing the stress distribution, and enhancing the anti-rotation performance, providing higher precision and longer service life for implant restoration.

[0027] A dental implant simulating the curvature of a natural tooth root is prepared using the design method for a dental implant simulating the curvature of a natural tooth root. The dental implant comprises an implant, an implant base and a center screw that cooperate with the implant; and a retention structure is provided on the outer surface of the implant.

[0028] The retention structure is set on the outer surface of the implant, which can increase the contact area between the implant and the bone tissue. It can take the form of threads, concave-convex structures or longitudinal grooves. It not only significantly improves the initial stability and bone integration efficiency of the implant, but also optimizes the stress distribution and improves the anti-rotation and anti-dislocation capabilities, thereby extending the service life of the implant and providing strong support for personalized implant applications under different bone conditions.

[0029] Preferably, the outer surface of the implant comprises roughened bumps.

[0030] By sandblasting to remove impurities on the surface of the implant, and then using acid etching to form tiny pores on the surface, the outer surface of the implant is made rougher, which can effectively increase the contact area between the implant and the alveolar bone. When the implant is implanted in the alveolar bone, bone cells can attach to the implant faster, accelerating the bone integration process.

[0031] A dental implant implantation system simulating the curvature of a natural tooth root comprises the dental implant simulating the curvature of a natural tooth root and an implantation cavity matching the size and cross-sectional shape of the dental implant.

[0032] Preferably, the implant cavity is drilled and formed by spiral milling hole technology of an oral implant robot.

[0033] Robotic spiral milling technology for oral implants uses a small-diameter milling cutter to continuously cut along a pre-set spiral trajectory. This allows for the creation of large-diameter holes while significantly improving chip removal efficiency and heat dissipation, effectively reducing the risk of damage to surrounding bone tissue caused by heat generation during surgery. Furthermore, this method allows for flexible programmable control of the milling path, enabling the creation of customized cavity shapes with non-circular cross-sections, thereby improving the fit between the cavity and the implant and enhancing initial stability.

[0034] Compared with the prior art, the beneficial effects of the present invention are embodied in: 1. The cross-sectional shape of each type of implant in the present invention can highly fit the cross-sectional shape of the root of its corresponding natural tooth, rather than the conventional circular cross-section, which significantly improves the adaptability and stability of the implant to the human oral environment.

[0035] 2. The cross-section of the dental implant of the present invention is non-circular. Compared with conventional implants with circular cross-sections, its size is not limited by the minimum bone volume, which can effectively increase the contact area between the implant and the bone and significantly enhance the anti-rotational stability.

[0036] 3. The implant cross-section general shape of the natural tooth morphology is specified, and the characteristic size of each type of implant is set, and the optimal curvature radius is set, which can realize the standardized design of the tooth implant with the natural tooth root curvature.

[0037] 4. The side wall inclination angle of the implant model is adjusted based on the natural tooth root morphology, which can effectively optimize the stress distribution, reduce local stress concentration, enhance the bone integration effect, and improve the manufacturing process and clinical adaptability.

[0038] 5. The retention structure and roughening protrusions are designed on the surface of the implant, which can significantly improve the initial stability and bone integration efficiency of the implant.

[0039] 6. The mating part of the implant model and the implant abutment model is set to a Morse taper of 5.7°, which can effectively improve the anti-rotation ability of the implant abutment and the tightness of the connection between the implant abutment and the implant. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A flowchart of a tooth implant design method with natural tooth root curvature for Example 1 is provided. Figure 2 A general shape diagram of the cross-section of each type of implant is provided. Figure 3 A single-root tooth implant overall structure diagram is provided. Figure 4 A double-root tooth implant overall structure diagram is provided. Figure 5 A three-root tooth implant overall structure diagram is provided. Wherein: 1-implant; 11-retention structure; 2-implant abutment; 3-center screw. DETAILED DESCRIPTION

[0041] In order to make the technical means, creative features, purposes and effects of the invention easy to understand, the invention will be further described in combination with specific drawings. However, the invention is not limited to the following examples.

[0042] It should be noted that the structure, proportion, size, etc. shown in the drawings attached to this specification are only used to cooperate with the content disclosed in the specification for understanding and reading by those skilled in the art, and do not define the limiting conditions for the implementation of the invention, so they do not have technical substantive significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the invention, should still fall within the scope of the technical content disclosed by the invention.

[0043] Example 1: The application provides a design method of a dental implant with a natural tooth root curvature, like Figure 1 as shown, comprising the following steps: S01, a general shape category designation step: in order to realize the scale production of the implant, based on the commonness of the cross-sectional shape characteristics of a plurality of natural tooth roots, the general shape of the cross section of each implant in the application is determined. In this embodiment, the general shape of the cross section of three types of implants is as shown in Figure 2 from left to right, the cross-sectional general shape of a single-root tooth implant, a double-root tooth implant and a triple-root tooth implant, wherein the cross-sectional curve of the single-root tooth implant is designed as an oval shape; the cross section of the double-root tooth implant adopts a symmetrical structure with four rounded corners and four recesses; and the cross section of the triple-root tooth implant is designed as a symmetrical shape containing three rounded corners and three recesses.

[0044] S02, a natural tooth three-dimensional model creation step: obtaining the head CBCT image data of a plurality of healthy volunteers, using a medical image processing software such as Mimics, extracting a plurality of three-dimensional models of different types of natural teeth saved as STL format for subsequent analysis, wherein the three-dimensional models of natural teeth are divided into single-root tooth models, double-root tooth models and triple-root tooth models based on the number of natural tooth roots.

[0045] Preferably, it also comprises a natural tooth three-dimensional model optimization step: since the human dentition is arranged closely, and the natural tooth root is connected closely with the alveolar bone, resulting in many defects in the natural tooth model extracted by using the medical image processing software such as Mimics in step S02, therefore, the created natural tooth model needs to be further imported into Geomagic Wrap, and the surface defects of the target tooth are removed by using the feature removal and rapid fairing functions to improve the model quality, and saved as an STL model.

[0046] S03, a curvature radius value range statistics step: based on the natural tooth model established in step S02, the upper end surface of each type of natural tooth is cut to obtain a plurality of cross sections, and the curvature radius value range of the tooth root cross-sectional curve is counted. For a single-root tooth, since its cross-sectional shape is relatively simple, only the curvature radius change range in one direction needs to be analyzed; and for a double-root tooth and a triple-root tooth, since their cross-sectional shape is more complex, the curvature change has directional differences, therefore, the curvature radius in the mesial-distal direction, the buccal-lingual direction and the included angle direction between the two directions is counted and analyzed respectively, so as to obtain the curvature radius value range of the double-root tooth and the triple-root tooth in different directions.

[0047] Further, the Gaussian curvature analysis and longitudinal section curvature analysis steps are also included: the Gaussian curvature, as an intrinsic geometric feature of the surface, can comprehensively reflect the coupling relationship between the two principal curvatures of the root surface. Compared with the analysis method of single section curvature, the Gaussian curvature can reveal the biomechanical nature of the natural tooth root in the stress process. Based on this characteristic, the natural tooth three-dimensional model established by the application is imported into the Geomagic Wrap software, the non-uniform rational B-spline surface is constructed by using the precise surface modeling function thereof, and finally saved as an entity model in the IGES format. Then the model is imported into the Rhino software, and the Gaussian curvature distribution image of the root surface is obtained through the built-in surface curvature analysis tool thereof. The root surface characteristics of each type of natural tooth are analyzed, specifically, for the single-root tooth, the Gaussian curvature of the root end region is greater than zero, indicating that the region presents a spherical curved feature; and the Gaussian curvature of the remaining most regions is zero, showing a flat structure such as a cylindrical surface or a plane. The root morphology of the double-root tooth and the three-root tooth is more complex: the pulp bottom region shows negative Gaussian curvature, showing a saddle-shaped hyperboloid feature; the root tip part still shows positive Gaussian curvature, that is, a spherical curved shape; in addition, the regions are mostly zero curvature regions, that is, flat structures.

[0048] The above results show that in the implant root morphology design process, the surface characteristics of different regions should be fully considered, especially the differentiated design of the middle and root tip parts. For this purpose, the longitudinal section of the natural tooth root in the mesial-distal direction is intercepted, and the longitudinal curvature characteristics are analyzed, and it is found that the longitudinal section curvature of the roots of the three types of natural teeth presents the characteristics of curve second-order continuity, that is, from the middle to the root tip, the curvature changes smoothly without mutation, and the root tip region maintains positive curvature.

[0049] Further, the principal curvature analysis step is also included: the principal curvature is a core parameter for describing the geometric shape of the root surface, which can reflect the maximum and minimum bending degree and the direction distribution of the surface at a certain point, so as to reveal the local mechanical transmission characteristics of the root surface, wherein the principal curvature of each point on the surface is composed of the maximum principal curvature and the minimum principal curvature. Through the principal curvature analysis, the principal curvature value range of different types of natural teeth in different regions (such as the middle and root parts) can be obtained.

[0050] S04, Implant feature size acquisition step: First, based on the CT data of the oral and maxillofacial of a plurality of healthy volunteers, a three-dimensional maxillofacial model is constructed using medical image processing software. On this basis, a plurality of size parameters of the alveolar bone space corresponding to each type of natural tooth are extracted, and each set of bone space size data includes key parameters such as interproximal distance, buccal-lingual width, and jaw height. Subsequently, the above bone space size data is converted into corresponding implant size parameters, and each set of implant size data includes mesial-distal direction diameter, buccal-lingual diameter, and implant length of the cross section of the upper end. Specifically, the conversion can be made with reference to the design standards of conventional implants, for example, the ideal distance between the implant center and the proximal interproximal side of the natural tooth is calculated as follows: D (distance between implant center and proximal interproxal side of natural tooth) = R (radius of implant) + 2 mm, the mesial-distal direction diameter of the implant is obtained, and the bone wall of 0.5 mm around the implant is reserved, and the buccal-lingual diameter of the implant should be at least 1 mm less than the original buccal-lingual bone width (0.5 mm on both sides). In terms of implant length, considering the existence of important anatomical structures such as maxillary sinus, nasal floor and mandibular canal at the bottom of the maxilla and mandible, in order to avoid damaging nerves and blood vessels and ensure safety, according to the implant design standard, the root end of the implant should maintain a safety distance of at least 1 mm from the above structures, thereby determining its length.

[0051] Then, a plurality of general categories are divided and the feature size of each general category is determined by statistically analyzing the plurality of implant size data of each type of implant. For example, after obtaining a plurality of implant size data of single tooth, it can be divided into three general categories according to the size distribution, and then the most common representative size is selected from the plurality of implant size data of each general category as the feature size of the single tooth implant, each feature size including mesial-distal direction diameter, buccal-lingual diameter and implant length. Thus, for single tooth implant, three representative size specifications can be mass-produced, thereby realizing standardized and classified design of implant size, and the specific size grouping can be determined in combination with actual conditions.

[0052] S05, implant upper end surface cross section design step: for each type of dental implant, according to its corresponding characteristic size, the specific form of the upper end surface cross section is optimized. In the S02 step, although the range of the curvature radius of each type of implant has been obtained through the root cross section analysis, this range is still insufficient to directly determine the optimal curvature parameter of the implant under different size conditions. Therefore, the present application uses the finite element simulation method to obtain the optimal curvature radius data matched with each characteristic size. Specifically, for each characteristic size of each type of implant, a plurality of simulation models are constructed respectively. Each model maintains the unified general form and size parameters of the implant, and only changes the value of the curvature radius, so as to compare the influence of different curvatures on the biomechanical properties of the implant under the same boundary conditions. In the finite element analysis process, the stress state of the human natural tooth in the mastication process is simulated: 100 N vertical load and 100 N lateral force in the 45° direction are applied at the crown part respectively, so as to reproduce the combined stress condition that may be encountered in the actual mastication process. Through simulation calculation, the stress peak value and stress distribution cloud diagram in the jaw bone are obtained, and then the mechanical performance of the implant under different curvature radii is evaluated, and the optimal curvature radius under the corresponding characteristic size is determined accordingly. Then the general form of the cross section, the characteristic size and the optimal curvature radius data are comprehensively considered to determine the specific form of the upper end surface cross section of each type of implant under each characteristic size.

[0053] S06, creating dental implant model step: by inputting the specific form of the upper end surface cross section and the corresponding characteristic size of the implant length, a three-dimensional model of each type of implant under each characteristic size is constructed by using three-dimensional software such as SOLIDWORKS.

[0054] Preferably, it also comprises an implant root form optimization step: based on the above-mentioned tooth root curve characteristics and tooth root longitudinal curvature characteristics, in the implant root form optimization step, the implant root is designed to present a second-order continuous smooth transition curve from the middle to the root tip direction, and a positive curvature feature is introduced in the root tip area to simulate the spherical bending feature of the natural tooth root end, so as to realize the stress distribution and bone integration effect more in line with the biomechanical characteristics.

[0055] Preferably, it also comprises an implant curvature regulation step: based on the natural tooth root main curvature value range, the implant curvature is regulated, and the control point of the implant surface is optimized, so that the main curvature distribution is closer to the biomechanical characteristics of the natural tooth root, thereby improving the adaptability and long-term stability of the implant and the surrounding bone tissue.

[0056] Further, the implant draft angle optimization design step is also included: the draft angle refers to a small inclination angle set on the structural side wall during the three-dimensional modeling and manufacturing process for the purpose of facilitating demolding, improving processing efficiency. Research has found that the natural tooth root is not completely perpendicular to the alveolar bone, but shows a natural inclination trend of about 5°, with a draft angle characteristic. Based on this physiological basis, the implant model is optimized for draft angle, and by adjusting the inclination angle of the implant model side wall, it is closer to the natural tooth root morphology, thereby optimizing stress distribution, reducing local stress concentration, enhancing bone integration effect, and improving manufacturing process and clinical adaptability.

[0057] Correspondingly, the implant abutment model matched with the multiple characteristic sizes of various dental implants is also designed, wherein the cross-sectional morphology of the implant abutment bottom and the implant connecting end face is consistent with the corresponding dental implant end cross-sectional morphology, realizing the precise matching and stable connection of the two in structure.

[0058] Preferably, the dental implant model optimization step is also included: based on the structural characteristics of the implant and implant abutment connecting area, the present application sets the Morse taper of the mating part of the implant abutment and the implant to 5.7° to improve the anti-rotation ability of the implant abutment. The Morse taper refers to the self-locking connection structure formed by the close fit of the tapered surface and the tapered surface between two mating parts. In the present application, the Morse taper is specifically defined as the included angle between the vertical central axis of the implant abutment connecting part and the extension direction of its side wall is 5.7°. This design makes the implant abutment form a self-locking fastening effect with the implant when subjected to axial pressure, thereby significantly improving the stability and sealing of the connection, optimizing the stress distribution, enhancing the anti-rotation performance, and providing higher precision and longer service life for implant restoration.

[0059] For the convenience of understanding the design method of the present application, some steps are explained below taking a single tooth implant as an example, and specific data are only examples: in S01 step, the cross-sectional shape of the single tooth implant is determined to be an ellipse, and the curvature radius value range of the corresponding natural tooth root cross section is obtained in S03 step. In S04 step, the bone space size data of a plurality of single tooth natural tooth roots are obtained and converted into implant size data, which are then divided into three groups of large, medium and small, each group containing a plurality of implant size data, and the data most representative of the size of each group are selected as the characteristic size of the data of the group; taking the small size group as an example, assuming that the characteristic size is 3 mm in the mesiodistal direction, 2 mm in the buccolingual direction, and 8 mm in the length of the implant. Subsequently, in S05 step, the finite element simulation method is used to evaluate the biomechanical performance under different curvature radii, and the optimal cross-sectional curvature radius under the size condition is selected as 1.6 mm. Thus, it is determined that the cross-sectional curve of the upper end surface of the small size single tooth implant is an ellipse with a diameter of 3 mm in the mesiodistal direction, a diameter of 2 mm in the buccolingual direction, and a curvature radius of 1.6 mm. Based on the above cross-sectional curve shape and the implant length of 8 mm, a three-dimensional model of the small size single tooth implant is constructed, and an implant abutment model matching the same is designed. Similarly, the three-dimensional modeling of the implants of the medium and large size groups of the single tooth implant and the design of the abutments matching the same are completed according to the same method; and further extended to the three-dimensional modeling of the large, medium and small sizes of other types of implants of double teeth, three teeth and the design of the matching abutments of the implants, so as to complete the modeling work of the whole implant system.

[0060] In addition, the present application also provides a tooth implant with a curvature similar to that of a natural tooth root, as shown in Figures 3 to 5 As shown, they are respectively the overall structure of a single tooth implant, a double tooth implant and a three tooth implant, mainly including an implant 1, an implant abutment 2 and a central screw 3. The outer surface of the implant 1 is further provided with a retention structure 11, which can increase the contact area of the implant 1 with the bone tissue, and can adopt the form of threads, concave-convex structures or longitudinal grooves, etc. Not only can it significantly improve the initial stability and osseointegration efficiency of the implant, but also can optimize the stress distribution, improve the anti-rotation and anti-displacement ability, thereby prolonging the service life of the implant 1, and providing strong support for personalized implant application under different bone conditions.

[0061] Further, in the present embodiment, the surface of the implant contains roughness protrusions; by sandblasting to remove impurities on the surface of the implant, and then using acid etching method to form small pores on the surface, the outer surface of the implant 1 is made more rough, which can effectively increase the contact area of the implant with the alveolar bone. When the implant 1 is implanted into the alveolar bone, bone cells can adhere to the implant 1 more quickly, accelerating the process of bone integration.

[0062] The application further provides a dental implant system with a natural tooth root curvature, comprising the dental implant with a natural tooth root curvature, and a implant cavity hole matched with the size and cross-sectional shape of the dental implant, which can be drilled and formed by a dental implant robot spiral hole milling technology. The dental implant robot spiral hole milling technology can continuously cut along a preset spiral trajectory by controlling a small-diameter milling cutter, thereby significantly improving the chip removal efficiency and heat dissipation performance while realizing the preparation of a large-diameter hole, and effectively reducing the damage risk of intraoperative heat production to the surrounding bone tissue. In addition, the method can flexibly program the milling path, and can process a personalized cavity shape with a non-circular cross-section, thereby improving the adaptability of the implant cavity and the implant, and enhancing the initial stability.

[0063] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and those skilled in the art should understand that the application includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the application will be included in the scope of the claims.

Claims

1. A method for designing a dental implant that simulates the curvature of a natural tooth root, characterized in that: include: S01. step of specifying a category of a general shape: specifying the general shapes of the cross sections of a single-root dental implant, a double-root dental implant, and a triple-root dental implant respectively; S02, step of creating a natural tooth three-dimensional model: creating a natural tooth model based on the head image data, wherein the natural tooth model is divided into a single-root tooth model, a double-root tooth model, and a triple-root tooth model; S03, a step of calculating the range of curvature radius values: obtaining a cross-section of the upper end surface of the root of the natural tooth based on the natural tooth model, and calculating the range of curvature radius values ​​for each type of natural tooth based on a plurality of the cross-sections of the upper end surface; S04. Implant characteristic size acquisition step: Based on the oral and maxillofacial CT data, multiple sets of bone space dimension data of the tooth roots of each type of natural tooth are acquired, the bone space dimension data are converted into multiple sets of implant dimension data, the implant dimension data are statistically divided into multiple general categories, and the characteristic dimensions of each general category are determined; S05. Implant upper end face cross-section design step: using finite element simulation, obtaining optimal curvature radius data corresponding to each characteristic dimension of each type of implant, and determining the specific shape of the upper end face cross-section that matches each type of implant at each characteristic dimension based on the cross-sectional characteristic shape, the characteristic dimension, and the optimal curvature radius data; S06. Step of creating a dental implant model: constructing an implant model based on the specific shape of the upper end face cross section and the characteristic dimensions; and designing an implant abutment model that matches the implant model, wherein the specific shape of the bottom cross section of the implant abutment model is consistent with the specific shape of the upper end face cross section.

2. The method for designing a dental implant simulating the curvature of a natural tooth root according to claim 1, wherein: The step between step S02 and step S03 also includes a natural tooth three-dimensional model optimization step, in which the tooth surface defects of the natural tooth model are optimized and removed.

3. The method for designing a dental implant simulating the curvature of a natural tooth root according to claim 1, wherein: Between step S02 and step S04, there are also Gaussian curvature analysis and longitudinal section curvature analysis steps, in which Gaussian curvature analysis is performed based on the natural tooth model to obtain the root surface characteristics of each natural tooth; the longitudinal section of the root of the natural tooth in the mesiodistal direction is obtained, and the longitudinal curvature characteristics of each type of natural tooth are obtained based on multiple longitudinal section analyses; after step S06, there is also an implant root morphology optimization step; the implant root morphology is optimized based on the longitudinal curvature characteristics, and the implant Gaussian curvature is adjusted to conform to the surface characteristics.

4. The method for designing a dental implant simulating the curvature of a natural tooth root according to claim 1, wherein: A principal curvature analysis step is also included between step S02 and step S04, in which the principal curvature value range of the root of each type of natural tooth is obtained based on the statistics of the natural tooth model; and an implant curvature control step is also included after step S06, so that the principal curvature of the implant model conforms to the principal curvature value range.

5. The method for designing a dental implant simulating the curvature of a natural tooth root according to claim 1, wherein: The step S06 is followed by an implant draft optimization design step, in which the side wall inclination angle of the implant model is adjusted based on the natural tooth root morphology.

6. The method for designing a dental implant simulating the curvature of a natural tooth root according to claim 1, wherein: The dental implant model optimization step is further included after the step S06, in which the side wall inclination angle of the matching part of the implant model and the implant abutment model is adjusted.

7. A dental implant with a curvature similar to that of a natural tooth root, characterized in that: A dental implant prepared by the method for designing a dental implant simulating the curvature of a natural tooth root as described in any one of claims 1 to 6, the dental implant comprising an implant (1), an implant base (2) cooperating with the implant (1), and a center screw (3); a retention structure (11) is provided on the outer surface of the implant (1).

8. The dental implant simulating the curvature of a natural tooth root according to claim 7, characterized in that: The outer surface of the implant (1) comprises roughened convex points.

9. A dental implant system that mimics the curvature of a natural tooth root, characterized by: A dental implant with a natural tooth root curvature as described in any one of claims 7-8, and also comprising an implant cavity matching the size and cross-sectional shape of the dental implant.

10. The dental implant system simulating the curvature of a natural tooth root according to claim 9, characterized in that: The implant cavity is drilled and formed by the spiral milling hole technology of the oral implant robot.

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