Personalized complete denture accurate manufacturing method based on multi-modal digital technology

Abstract

The invention discloses a personalized complete denture precise manufacturing method based on a multi-modal digital technology, and relates to the technical field of oral restoration engineering and digital medical treatment. According to the method, firstly, three-modal data acquisition of oral soft tissue, facial aesthetics and alveolar bone anatomy is completed through an intraoral scanner, surface scanning equipment and CBCT; performing precise registration through an ICP algorithm to generate an integrated model; a virtual jaw frame and intelligent tooth arrangement software are combined to complete personalized design; for special cases, a transition / temporary denture and a biocompatibility tissue regulator are adopted to realize dynamic adaptation; and finally, completing false tooth manufacturing and verification through 3D printing or five-axis cutting. The method solves the problems that a traditional method is low in precision, weak in special case treatment and the like, achieves anatomy-function-aesthetics synergistic repair of the false tooth, and has the advantages of being high in adaptation degree, short in period and less in revival.

Description

Technical Field

[0001] This invention relates to the fields of oral restoration engineering and digital medical technology, and in particular to a method for precise fabrication of personalized complete dentures based on multimodal digital technology. Background Technology

[0002] (I) The core limitations of traditional complete denture fabrication

[0003] Traditional complete dentures rely on manual impressions, wax rim positioning, and manual tooth arrangement, which have three major drawbacks: First, significant accuracy errors occur, as manual impressions are affected by saliva and soft tissue deformation, resulting in errors of 0.3-0.5mm, leading to more than 80% of patients requiring multiple follow-up visits for adjustments; second, there is insufficient capacity to handle special cases, as patients requiring immediate tooth extraction need to wait 3-6 months for bone healing, and the denture loss rate in cases of low / defective alveolar ridges is as high as 40%; third, there is reliance on the technician's experience, resulting in poor consistency in dentures made by different operators, making it difficult to guarantee occlusal accuracy and aesthetic results.

[0004] (II) Bottlenecks in the application of existing digital technologies

[0005] Existing digital dental technologies (intraoral scanning, 3D printing, etc.) have significant shortcomings: their application is limited, often employing a simple "scanning + printing" process without integrating multimodal data such as facial scanning and CBCT, resulting in disharmony between prosthesis function and facial aesthetics; they lack case-specific processes, with existing solutions only applicable to routine cases with good alveolar ridge conditions, failing to meet the dynamic adaptation needs of special cases; and their data fusion capabilities are insufficient, with data from each device stored independently, leading to large registration errors and making it difficult to achieve synergistic optimization of "anatomy-function-aesthetics". Summary of the Invention

[0006] To address the technical problems existing in the background art, this invention proposes a method for precise fabrication of personalized complete dentures based on multimodal digital technology.

[0007] The method for precise fabrication of personalized complete dentures based on multimodal digital technology proposed in this invention includes the following steps:

[0008] (1) Multimodal data acquisition: Intraoral scanner, facial scanning device and CBCT device were used to acquire three-dimensional data of the patient's oral soft tissue, three-dimensional aesthetic data of the face and three-dimensional anatomical data of the alveolar bone respectively;

[0009] (2) Data fusion processing: Based on the CBCT alveolar bone anatomical landmarks, the ICP iterative nearest point algorithm is used to register the three-modal data;

[0010] (3) Personalized denture design: The integrated model is imported into CAD design software, and the virtual jaw system is combined to simulate the movement trajectory of the mandible. The intelligent tooth arrangement software matches facial aesthetic parameters and chewing habits to generate an initial design plan for complete dentures.

[0011] (4) Special case adaptation treatment: For special cases such as immediate tooth extraction, low / defective alveolar ridge, poorly made complete dentures, and abnormal occlusal relationship, biocompatible tissue modifier is filled into the veneer surface of the base of the transitional denture or temporary denture.

[0012] (5) Precision manufacturing and verification: Permanent dentures are made using 3D printing or five-axis cutting technology and inspected by laser scanning.

[0013] Furthermore, in step (1):

[0014] Intraoral scanning accuracy ≤ 0.02 mm, CBCT reconstruction slice thickness ≤ 0.1 mm, facial feature point extraction error ≤ 0.03 mm;

[0015] Intraoral scan data format is STL, point cloud density is ≥1000 points / mm², and scan overlap rate is ≥80%;

[0016] The area scan data is compatible with OBJ / PLY format, with a point pitch of 0.1mm and a depth of field of 120mm.

[0017] CBCT data are in DICOM3.0 format, with a field of view (FOV) ≥16×13cm, a matrix ≥512×512, and a bone tissue CT value measurement range of 200-1500HU.

[0018] Furthermore, in step (2):

[0019] After ≥50 iterations and registration with a root mean square error ≤0.05mm, an integrated 3D model is generated.

[0020] The triangular mesh density of the integrated 3D model is ≥5000 faces / cm³, and the registration reference points include the opening of the mandibular nerve canal, the nasal alar base point, and the alveolar ridge apex.

[0021] Furthermore, in step (3):

[0022] The virtual jaw system can simulate the mandibular trajectory with an opening degree of 0-40mm and a lateral movement angle of 0-8°, with an occlusal accuracy of ≤0.01mm;

[0023] The intelligent tooth alignment software has multiple artificial tooth databases built-in, which can automatically match facial parameters, align teeth with an overbite of 1-2mm and an overjet of 2-3mm, and set the Spee curve curvature radius to 25-30mm.

[0024] Furthermore, in step (4):

[0025] The modulator has a tensile strength ≥1.5MPa and biocompatibility that meets ISO10993-1 standards. After wearing the modulator for 4-8 weeks, personalized jaw position relationship and fitting morphology data are obtained by scanning.

[0026] Furthermore, in step (4):

[0027] The tissue modifiers are polysiloxanes, polymethyl methacrylates containing hydroxyapatite, or silicone rubbers. Among them, the modifiers containing hydroxyapatite have a particle size of 50-100μm, a content of 20wt%, and a degradation rate of 0.1mm / month.

[0028] Furthermore, in step (4), the handling of special cases specifically includes:

[0029] For cases requiring immediate tooth extraction: a transitional denture is fabricated within one week after extraction, with a 0.5-1mm space reserved on the occlusal surface of the denture base for adjustment filling. Bone resorption is monitored weekly, and adjustment filling is added when bone resorption exceeds 0.2mm.

[0030] Cases of low alveolar ridge: The posterior region of the temporary denture is filled with a 1.5mm thick tissue modifier. After wearing it for 2-3 weeks, a stable support surface is formed. The thickness of the posterior region of the permanent denture base is ≥3.0mm.

[0031] Case of alveolar ridge defect: The temporary denture defect area is designed with a personalized filling structure, and the permanent denture base adopts a honeycomb reinforced structure with a hole diameter of 2mm, a wall thickness of 0.5mm, and an extension covering the defect edge of ≥2mm.

[0032] Furthermore, in step (5):

[0033] The 3D printing layer thickness is ≤0.05mm, the five-axis cutting speed is ≥30000r / min, and the denture accuracy error is ≤0.1mm.

[0034] Furthermore, in step (5):

[0035] The 3D printing uses dental-grade resin with a shrinkage rate of ≤0.5%. After printing, it is cured with 405nm UV light for 30 minutes, resulting in a surface roughness Ra≤0.8μm.

[0036] The five-axis cutting roughing speed is 25,000 r / min, the finishing speed is 35,000 r / min, the cutting tool diameter is 0.8 mm, the sintering temperature of the zirconia artificial tooth is 1500℃, and the holding time is 2 hours.

[0037] Furthermore, the personalized complete denture precision fabrication method based on multimodal digital technology also includes an effect verification step: using a universal testing machine to test the denture retention force to be ≥15N, and using a chewing simulator... After one fatigue test, the deformation of the denture was ≤0.05mm, and no cracks were generated.

[0038] The beneficial effects of this invention are:

[0039] (1) Significantly improves the precision and fit of denture restoration, ensuring the restoration effect.

[0040] (1.1) Multimodal data fusion to achieve accurate modeling: Based on the anatomical landmarks of alveolar bone in CBCT, the intraoral scan, facial scan and CBCT three-modal data registration is completed by ICP iterative nearest point algorithm. After registration, the root mean square error is ≤0.05mm. The generated integrated three-dimensional model has a triangular mesh density of ≥5000 faces / cm³, which accurately replicates the three-dimensional relationship of the patient's "alveolar bone-oral soft tissue-facial morphology". It solves the problems of large error (0.3-0.5mm) in traditional manual impression and isolated data in existing single digital technology, and lays the data foundation for accurate denture design.

[0041] (1.2) Personalized design takes into account both function and aesthetics: Combining a virtual jaw system (which can simulate an opening of 0-40mm, a lateral movement angle of 0-8°, and a mandibular trajectory, with an occlusal accuracy of ≤0.01mm) with intelligent tooth arrangement software (which automatically matches facial parameters, arranging teeth with an overbite of 1-2mm and an overjet of 2-3mm), the dentures not only conform to the physiological trajectory of mandibular movement, but also match the aesthetic features of the patient's face, achieving the three-in-one restoration goal of "anatomy-function-aesthetics", avoiding the drawbacks of traditional dentures such as "occlusal disorder" and "uncoordinated facial appearance".

[0042] (1.3) Excellent mechanical properties and durability of finished dentures: Dentures manufactured by 3D printing (layer thickness ≤ 0.05 mm, resin shrinkage ≤ 0.5%) or five-axis cutting (speed ≥ 30000 r / min) processes have a precision error ≤ 0.1 mm and have passed effect verification: retention force ≥ 15 N, after 10 6 After one chewing fatigue test, the deformation is ≤0.05mm and there are no cracks, which can meet the long-term chewing needs of patients and greatly reduce the probability of denture breakage and loss.

[0043] (2) Strengthen the ability to handle special cases and fill the technical gaps in the industry.

[0044] (2.1) Achieving dynamic adaptation for special cases: For complex cases such as immediate tooth extraction, low alveolar ridge / defect, etc., a full-cycle solution of "transitional denture / temporary denture + biocompatible tissue modifier (tensile strength ≥1.5MPa, conforming to ISO10993-1 standard)" is adopted, which can dynamically adapt to changes in oral morphology. For example, in cases of immediate tooth extraction, a transitional denture can be worn within 1 week after extraction, and the modifier can compensate for bone resorption (replenish in time when bone resorption is >0.2mm), without waiting for 3-6 months for bone healing; the permanent denture base for cases with alveolar ridge defects adopts a honeycomb-shaped reinforced structure, extending and covering the defect edge ≥2mm, which solves the pain point of high denture loss rate (up to 40%) in special cases using traditional techniques.

[0045] (2.2) Obtain personalized jaw position data: After the patient wears the transitional denture / temporary denture for 4-8 weeks, the fitting morphology data is obtained by scanning, and the denture design plan is optimized in reverse so that the final denture fits the patient's individual oral condition better and reduces the probability of follow-up visits for adjustment due to jaw position deviation.

[0046] (3) Significantly improves diagnostic and treatment efficiency and reduces time costs for doctors and patients.

[0047] (3.1) Shorten the production and treatment cycle: The fully digital operation replaces the tedious steps of traditional manual impression making and wax pattern making. Combined with the dynamic adaptation process for special cases, the production cycle of complete dentures is shortened by 60%, and the number of follow-up visits for patients is reduced by 70% (traditionally 5-7 visits are required, but this method only requires 2-3 visits). This not only reduces the burden of patients having to make multiple trips to the hospital, but also improves the treatment turnover rate of medical institutions.

[0048] (3.2) Reduce reliance on technician experience: Standardized digital processes (data collection - model fusion - intelligent design - precision manufacturing) make denture fabrication less dependent on the "hand feel" of senior technicians. New practitioners can master the core operations after simple training. At the same time, electronic data archives facilitate case review and parameter optimization, improving the operability of clinical teaching and research.

[0049] (4) Promotes technological upgrading in the industry and has broad industrial application value.

[0050] (4.1) Breaking through the bottleneck of existing digital technology application: For the first time, the precise fusion of three-modal data and the digital collaborative application of tissue modulators have been realized, solving the shortcomings of existing digital technologies such as "single application" and "insufficient data fusion capability", and establishing a complete technical chain for digital restoration of complete dentures.

[0051] (4.2) Adaptable to mainstream equipment and low threshold for promotion: The technical solution is compatible with mainstream intraoral scanners, CBCT, 3D printers and other equipment on the market. No special hardware needs to be customized. Small and medium-sized dental clinics and denture processing plants can gradually introduce it, which is conducive to popularization in primary medical institutions and promotes the transformation of complete denture restoration from "expert-led" to "standardized service".

[0052] (4.3) Establishing industry technical standards: A full-chain technical standard of "multimodal data acquisition - electronic bite record - dynamic optimization - intelligent manufacturing" has been constructed, providing a replicable technical framework for the industry to move from "manual dominance" to the era of "digital standardization", and has the potential to become an industry benchmark. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0054] Reference Figure 1 The present invention proposes a method for precise fabrication of personalized complete dentures based on multimodal digital technology, comprising the following steps:

[0055] (1) Multimodal data acquisition

[0056] This step requires the simultaneous acquisition of three types of 3D data: oral soft tissue, facial aesthetics, and alveolar bone anatomy. This ensures data accuracy and format compliance, laying the foundation for subsequent fusion modeling.

[0057] (1.1) Equipment selection and parameter setting

[0058] (1.1.1) Intraoral scanner: A high-precision dental intraoral scanner was selected, with a scanning accuracy of ≤0.02mm, data format of STL, point cloud density of ≥1000 points / mm², and scanning overlap rate of ≥80%. During scanning, the edentulous mucosa of the patient's upper and lower jaws was scanned in sections, with a focus on key areas such as the alveolar ridge crest and vestibule to avoid data loss due to saliva interference, and finally a complete three-dimensional model of oral soft tissue was generated.

[0059] (1.1.2) Facial scanning equipment: A portable 3D facial scanner was used, compatible with OBJ / PLY data formats, with a point spacing of 0.1mm and a depth of field of 120mm. The facial feature point extraction error was ≤0.03mm. Facial data from three perspectives (front, left and right sides) were collected with the patient in a natural head position and relaxed state. The focus was on capturing aesthetic landmarks such as the nasal alar base, corner of the mouth, and chin point for subsequent denture aesthetic matching.

[0060] (1.1.3) CBCT Equipment: A dental-specific CBCT machine was used, with data format DICOM3.0, reconstruction slice thickness set to ≤0.1mm, scanning field of view (FOV) ≥16×13cm, matrix ≥512×512, and bone tissue CT value measurement range of 200-1500HU. During the scan, the patient's head was kept fixed to accurately acquire three-dimensional data of anatomical landmarks such as the opening of the mandibular nerve canal and the apex of the alveolar ridge, clarifying the alveolar bone morphology and bone mass distribution.

[0061] (1.2) Data quality control

[0062] After the scan is completed, the data integrity is verified using the device's built-in software: intraoral scans must be free of obvious holes or noise, facial scans must have complete facial feature point recognition, and CBCT scans must be free of artifacts and have clear anatomical structures. Unqualified data must be re-acquired.

[0063] (2) Data fusion processing

[0064] Based on CBCT alveolar bone anatomical landmarks, the ICP iterative nearest point algorithm was used to complete the registration of three-modal data, generate an integrated three-dimensional model, and achieve the coordinated unification of "anatomical-soft tissue-aesthetic" data.

[0065] (2.1) Selection of registration reference points

[0066] In the CBCT reconstruction model, the mandibular nerve canal opening, the nasal alar base, and the alveolar ridge apex are manually marked as core reference points. These types of landmarks have stable anatomical positions and can be used as anchor points for cross-modal data registration.

[0067] (2.2) ICP Algorithm Registration Operation

[0068] Intraoral and facial scan data were imported into medical image fusion software. Using CBCT reference points, ICP iterative registration was initiated, with the number of iterations set to ≥50, until the root mean square error (RMSE) after registration was ≤0.05mm. During the registration process, the software automatically aligned the spatial coordinates of different modal data to eliminate data deviations.

[0069] (2.3) Integrated Model Generation and Optimization

[0070] After registration, an integrated 3D model of "alveolar bone-oral soft tissue-facial morphology" is generated. The model's triangular mesh density is adjusted to ≥5000 faces / cm³ to ensure a smooth surface and complete details. At the same time, redundant data is deleted to reduce the computational burden on subsequent design stages.

[0071] (3) Personalized denture design

[0072] By importing the integrated model into dental CAD design software and combining it with a virtual articulation system and intelligent tooth alignment software, both the function and aesthetics of the prosthesis can be optimized, generating an initial design scheme.

[0073] (3.1) Setting parameters for the virtual jaw system

[0074] In the CAD software, the virtual jaw module is invoked, and the mandibular movement trajectory parameters are set: opening degree 0-40mm, lateral movement angle 0-8°, and occlusal accuracy ≤0.01mm. The jaw position data of the integrated model is imported into the system to simulate the patient's natural mandibular movement, identify potential occlusal interference areas, and determine reasonable vertical distances and centric jaw positions.

[0075] (3.2) Generation of intelligent tooth alignment scheme

[0076] The intelligent tooth alignment software is activated, accessing multiple built-in artificial tooth databases. The software automatically matches the patient's facial parameters (such as lower third facial height and facial contour) and combines them with chewing habit data, adhering to the following tooth alignment standards: overbite 1-2mm, overjet 2-3mm, and Spee curve radius 25-30mm. After tooth alignment is completed, the dentist can manually fine-tune the position of the artificial teeth to ensure uniform occlusal contact and facial aesthetic harmony.

[0077] (3.3) Initial scheme verification

[0078] The design scheme is subjected to three-dimensional simulation analysis to check the extension range of the denture base edge, the symmetry of the artificial tooth arrangement, and the distribution of occlusal contact points. After confirming that there are no design defects, the initial denture model in STL format is output.

[0079] (4) Adaptation and treatment of special cases

[0080] For special cases such as immediate tooth extraction, low alveolar ridge / defect, a "transitional denture / temporary denture + biocompatible tissue modifier" approach is adopted to achieve dynamic adaptation of oral morphology and obtain personalized jaw position relationship data.

[0081] (4.1) Selection of tissue modifiers: Select modifiers that meet the ISO10993-1 biocompatibility standard, with a tensile strength ≥1.5MPa. Specifically, polysiloxanes, polymethyl methacrylate containing hydroxyapatite, or silicone rubber can be selected. Among them, modifiers containing hydroxyapatite must meet the following parameters: particle size 50-100μm, content 20wt%, and degradation rate 0.1mm / month.

[0082] (4.2) Adaptation procedures for different special cases

[0083] (4.2.1) Immediate extraction cases: Within one week after the patient's extraction, a transitional denture is fabricated based on the initial integrated model. A 0.5-1mm space for adjustment agent filling is reserved in the area where the denture base fits the alveolar socket. After injecting the tissue adjustment agent, the denture is worn. During the wearing period, alveolar bone resorption is monitored weekly by intraoral scanning. If the bone resorption is >0.2mm, adjustment agent is added in time to ensure denture fit. After 4-8 weeks, when the bone resorption has stabilized, the fitting morphology data is obtained by scanning.

[0084] (4.2.2) Cases of low alveolar ridge: When fabricating temporary dentures, fill the veneer surface of the denture base with a 1.5mm thick tissue adjustment agent and instruct the patient to wear it for 2-3 weeks to allow the adjustment agent to form a stable support surface according to the pressure shape of the mucosa; optimize the design of permanent dentures based on fitting data to ensure that the thickness of the permanent denture base in the posterior tooth area is ≥3.0mm to improve denture retention;

[0085] (4.2.3) Cases of alveolar ridge defects: A personalized filling structure is designed in the corresponding area of ​​the temporary denture defect, and a tissue adjustment agent is used to compensate for the defect space; the permanent denture base adopts a honeycomb reinforced structure (pore diameter 2mm, wall thickness 0.5mm), and the base extends to cover the defect edge ≥2mm to enhance the structural strength and fit of the denture.

[0086] (4.3) Data collection of fitting: After the patient wears the transitional denture / temporary denture for 4-8 weeks, the actual fitting shape and jaw position relationship data of the denture are obtained again by intraoral scanning. The data is then imported into CAD software to optimize the initial denture design.

[0087] (5) Precision manufacturing and verification

[0088] Permanent dentures are fabricated using 3D printing or five-axis machining processes, and laser scanning is used to ensure that the accuracy meets the standards.

[0089] (5.1) Implementation of 3D printing process

[0090] (5.1.1) Materials and parameters: Select dental resin (shrinkage rate ≤0.5%), set the printing layer thickness ≤0.05mm, and start the printing equipment to complete the integrated molding of the denture base and artificial teeth;

[0091] (5.1.2) Post-processing: After printing, the denture is placed in a 405nm UV curing device for 30 minutes and then polished to make the surface roughness Ra≤0.8μm.

[0092] (5.2) Implementation of five-axis cutting process

[0093] Roughing and finishing: Zirconia blanks were selected, and the roughing speed was set to 25,000 r / min and the finishing speed to 35,000 r / min. The diameter of the cutting tool was 0.8 mm. The denture was cut according to the optimized model. The zirconia artificial teeth need to be sent into the sintering furnace and sintered at 1500℃ for 2 hours.

[0094] (5.3) Laser scanning detection

[0095] A laser scanner is used to perform full-size inspection on the completed dentures. The overall accuracy error of the dentures must be ≤0.1mm. If the inspection fails, the dentures must be returned to the design stage for optimization and re-manufacturing.

[0096] (6) Effect verification

[0097] Mechanical performance and durability tests are conducted on finished dentures to ensure their safety and stability in clinical use;

[0098] (6.1) Retention force test

[0099] The denture was fixed on a test bench simulating the mucosa of an edentulous jaw, and a universal testing machine was used to test the vertical retention force. The denture retention force was required to be ≥15N to ensure that it would not easily fall off when worn.

[0100] (6.2) Fatigue durability test

[0101] Install the denture into the chewing simulator, set the simulated chewing frequency and force, and complete 10 steps. 6 After a fatigue test, the denture deformation was checked and found to be ≤0.05mm with no cracks, confirming that the denture can meet long-term chewing needs.

[0102] (6.3) Clinical trial and verification

[0103] The qualified dentures are delivered to the patient for trial fitting to check the occlusion, retention, and facial aesthetics. Once the patient has no obvious discomfort and normal chewing function, the complete denture restoration process is completed.

[0104] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for precise fabrication of personalized complete dentures based on multimodal digital technology, characterized in that, Includes the following steps: (1) Multimodal data acquisition: Intraoral scanner, facial scanning device and CBCT device were used to acquire three-dimensional data of the patient's oral soft tissue, three-dimensional aesthetic data of the face and three-dimensional anatomical data of the alveolar bone respectively; (2) Data fusion processing: Based on the CBCT alveolar bone anatomical landmarks, the ICP iterative nearest point algorithm is used to register the three-modal data; (3) Personalized denture design: The integrated model is imported into CAD design software, and the virtual jaw system is combined to simulate the movement trajectory of the mandible. The intelligent tooth arrangement software matches facial aesthetic parameters and chewing habits to generate an initial design plan for complete dentures. (4) Special case adaptation treatment: For special cases such as immediate tooth extraction, low / defective alveolar ridge, poorly made complete dentures, and abnormal occlusal relationship, biocompatible tissue modifier is filled into the veneer surface of the base of the transitional denture or temporary denture. (5) Precision manufacturing and verification: Permanent dentures are made using 3D printing or five-axis cutting technology and inspected by laser scanning.

2. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (1): Intraoral scanning accuracy ≤ 0.02 mm, CBCT reconstruction slice thickness ≤ 0.1 mm, facial feature point extraction error ≤ 0.03 mm; Intraoral scan data format is STL, point cloud density is ≥1000 points / mm², and scan overlap rate is ≥80%; The area scan data is compatible with OBJ / PLY format, with a point pitch of 0.1mm and a depth of field of 120mm. CBCT data are in DICOM3.0 format, with a scanning field of view (FOV) ≥16×13cm, a matrix ≥512×512, and a bone tissue CT value measurement range of 200-1500HU.

3. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (2): After ≥50 iterations and registration root mean square error ≤0.05mm, an integrated 3D model is generated. The triangular mesh density of the integrated 3D model is ≥5000 faces / cm³, and the registration reference points include the opening of the mandibular nerve canal, the nasal alar base point, and the alveolar ridge apex.

4. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (3): The virtual jaw system can simulate the mandibular trajectory with an opening degree of 0-40mm and a lateral movement angle of 0-8°, with an occlusal accuracy of ≤0.01mm; The intelligent tooth alignment software has multiple artificial tooth databases built-in, which can automatically match facial parameters, align teeth with an overbite of 1-2mm and an overjet of 2-3mm, and set the Spee curve curvature radius to 25-30mm.

5. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (4): The modulator has a tensile strength ≥1.5MPa and biocompatibility that meets ISO10993-1 standards. After wearing the modulator for 4-8 weeks, personalized jaw position relationship and fitting morphology data are obtained by scanning.

6. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (4): The tissue modifiers are polysiloxanes, polymethyl methacrylates containing hydroxyapatite, or silicone rubbers. Among them, the modifiers containing hydroxyapatite have a particle size of 50-100μm, a content of 20wt%, and a degradation rate of 0.1mm / month.

7. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (4), the handling of special cases specifically includes: For cases requiring immediate tooth extraction: a transitional denture is fabricated within one week after extraction, with a 0.5-1mm space reserved on the occlusal surface of the denture base for adjustment filling. Bone resorption is monitored weekly, and adjustment filling is added when bone resorption exceeds 0.2mm. Cases of low alveolar ridge: The posterior region of the temporary denture is filled with a 1.5mm thick tissue modifier. After wearing it for 2-3 weeks, a stable support surface is formed. The thickness of the posterior region of the permanent denture base is ≥3.0mm. Case of alveolar ridge defect: The temporary denture defect area is designed with a personalized filling structure, and the permanent denture base adopts a honeycomb reinforced structure with a hole diameter of 2mm, a wall thickness of 0.5mm, and an extension covering the defect edge of ≥2mm.

8. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, In step (5): The 3D printing layer thickness is ≤0.05mm, the five-axis cutting speed is ≥30000r / min, and the denture accuracy error is ≤0.1mm.

9. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 8, characterized in that, In step (5): The 3D printing uses dental-grade resin with a shrinkage rate of ≤0.5%. After printing, it is cured with 405nm UV light for 30 minutes, resulting in a surface roughness Ra≤0.8μm. The five-axis cutting roughing speed is 25,000 r / min, the finishing speed is 35,000 r / min, the cutting tool diameter is 0.8 mm, the sintering temperature of the zirconia artificial tooth is 1500℃, and the holding time is 2 hours.

10. The method for precise fabrication of personalized complete dentures based on multimodal digital technology according to claim 1, characterized in that, It also includes an effectiveness verification step: using a universal testing machine to test the denture retention force to be ≥15N, and using a chewing simulator... After one fatigue test, the deformation of the denture was ≤0.05mm, and no cracks were generated.

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