Natural tooth secondary immediate repair method, zirconium oxide prosthesis and digital processing technology of zirconium oxide prosthesis

Abstract

The invention relates to a natural tooth secondary immediate restoration system, which comprises a restoration method, a zirconium oxide restoration body and a digital processing technology thereof, belongs to the field of tooth restoration, and aims to solve the problems of periodontitis and aesthetics incoordination caused by long period and biological width invasion of traditional secondary restoration. According to the technical scheme, the method is characterized in that a symmetric bone margin curve is rapidly established through biological modification in an operation preparation stage and is perpendicular to a prepared tooth body, alveolar bone and gingiva data are obtained through digital scanning, and design, cutting, sintering and neck high polishing treatment (without decorative porcelain) of a zirconium oxide restoration are completed within 12 hours in a technician room. Immediate tooth wearing is realized by using a self-curing bonding material, and indexes are monitored in combination with postoperative reexamination; the dental implant is mainly used for immediate repair of natural teeth, remarkably shortens the treatment cycle, and reduces the chair-side time and the number of times of revival.

Description

Technical Field

[0001] This invention relates to the field of dental restoration, and in particular to a method for immediate secondary restoration of natural teeth, zirconia restorations, and a digital processing technology for zirconia restorations. Background Technology

[0002] In clinical practice of prosthodontics, cases of failed natural tooth restorations commonly involve problems related to health maintenance, functional restoration, and aesthetic results. In traditional restorative treatments, in order to balance periodontal health and the patient's aesthetic needs, dentists often need to prepare the tooth, especially in the aesthetic zone, to a relatively deep subgingival position. This can easily infringe on the biological width, causing inflammation, tissue damage, and aesthetic disharmony in the soft and hard tissues surrounding the restoration. At the same time, in secondary restorative treatments, patients generally have significant concerns about the lengthy treatment period, large surgical trauma, and frequent follow-up visits.

[0003] Traditional secondary restorations often employ a phased treatment model. For example, after crown lengthening surgery, patients need to wait 3-6 months for the periodontal tissues to stabilize before the final restoration can be performed. This process is lengthy and the patient experience is unsatisfactory. In addition, the biocompatibility of the restoration materials is insufficient, and the processing technology is complex, making it difficult to simultaneously meet the clinical effect and aesthetic requirements of immediate restoration. Summary of the Invention

[0004] This invention provides a method for immediate secondary restoration of natural teeth, a zirconia restoration, and a digital processing technology for the zirconia restoration, in order to solve the above-mentioned technical problems;

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] The first aspect is the method for immediate secondary restoration of natural teeth, which includes the following steps:

[0007] Step (1) Initial stage: Conduct periodontal assessment and oral hygiene education and guidance for the patient;

[0008] Step (2) Surgical preparation stage: Remove the original restoration, make an incision in the gingival sulcus and a vertical relaxation incision, open the full-thickness flap and remove residual tissue to expose the surgical area, determine the bony landmarks and trim the labial bone margin to form a symmetrical bone margin curve, use the vertical preparation method to re-prepare the tooth, scan the data of the trimmed alveolar bone, prepared tooth and other teeth, gingiva and occlusion, and scan the complete data of the intraoral cavity again after the surgical area is sutured;

[0009] Step (3) Technician's processing stage: Receive scan data and check its integrity, perform data design to confirm parameters such as edge line position and placement path direction, after the doctor confirms the plan, digitally cut the zirconia crown, and then perform sintering, cooling, grinding and shaping, glazing and polishing.

[0010] Step (4) Immediate tooth fitting stage: Try on the zirconia restoration, check the position, margins, etc., then perform intraoral bonding, remove the sutures and place the rubber camphor, remove the excess adhesive, then reposition the tooth and suture it in place, check and adjust the bite.

[0011] Step (5) Postoperative follow-up stage: Postoperative follow-up examinations are conducted periodically, and relevant indicators are recorded.

[0012] Furthermore, in step (2), the tooth is re-prepared using a vertical preparation method and a BOPT bur set to obtain a higher dentin shoulder and correct the asymmetrical long axis of the tooth, thereby increasing the interdental distance.

[0013] Furthermore, in step (2), the skeletal markers include the location of the cementoenamel junction and the alveolar ridge crest, and the labial skeletal margin is trimmed to the position 2mm apical to the labial CEJ.

[0014] Furthermore, in step (3), the data types received by the technical room include STL, DCM, and PLY files. The processing time is about 12 hours, of which the time for digital cutting, sintering and cooling, and morphological finishing, glazing and dyeing is about 6 hours.

[0015] Furthermore, in step (3), the design of the zirconia crown conforms to the neck shape of BOPT, and the neck is highly polished without decorative porcelain or glaze.

[0016] Furthermore, in step (4), 3MLuting2 glass ionomer adhesive is used for intraoral bonding, and a bonding material with good fluidity and self-curing properties is selected.

[0017] Furthermore, in step (5), the follow-up period includes one week, one month, two months, three months, six months and 12 months after surgery, and the recorded indicators include PI, BOP, PPD, periapical radiographs and intraoral photographs.

[0018] Secondly, a digital processing technology for zirconia restorations includes the following steps:

[0019] S1 Data Acquisition: Scans and trims alveolar bone, hard tissue data of prepared teeth, and other intraoral teeth, gingiva, and occlusal data, generating STL, DCM, or PLY format files;

[0020] S2 Data Processing and Design: Check data integrity, confirm edge line position and placement path direction, set gap parameters, select tooth data, design restoration model conforming to BOPT cervical morphology, and have the dentist confirm compliance;

[0021] S3 processing and fabrication: Based on the confirmed model, the zirconia blank is digitally cut, and the cut zirconia crown is sintered, naturally cooled, polished and shaped, glazed and polished at the neck. The total processing time is within 12 hours.

[0022] Furthermore, in step S3, the digital cutting time is 1.5-2 hours, the total time for sintering and natural cooling is within 5 hours, and the time for grinding, shaping, glazing, and neck polishing is about 1 hour.

[0023] Thirdly, a zirconia restoration includes a crown body and a neck structure, wherein the neck structure is located 2 mm coronally to the alveolar ridge crest, corresponding to 2 mm apically to the cementoenamel junction, and extends 1 mm into the gingival sulcus; the surface of the neck structure is highly polished and has no enamel or porcelain enamel layer.

[0024] The beneficial effects of this invention are as follows:

[0025] In the surgical preparation stage, biological reshaping (BS) is used to quickly establish a hard tissue morphology that meets the healing requirements, and precise hard tissue data is directly obtained through digital scanning. In the laboratory stage, digital processing technology based on biocompatible materials (zirconia) is used (design, cutting, sintering and other processes are completed within 12 hours) to achieve rapid fabrication of the restoration. In the immediate placement stage, biologically compliant bonding methods (such as selecting self-curing materials with good flowability) reduce placement obstacles. The entire process does not require waiting for the long-term stabilization period of periodontal tissue in traditional treatments, significantly reducing the patient's chair time, number of treatments and total cycle. Attached Figure Description

[0026] Figure 1 This is a diagram showing the process before repair.

[0027] Figure 2 This is a schematic diagram after the repair. Detailed Implementation

[0028] In order to make the content of the present invention easier to understand, the technical solutions in the embodiments of the present invention are described clearly and completely;

[0029] Example 1

[0030] First, let me introduce the method for immediate secondary restoration of natural teeth, which includes the following steps:

[0031] Step (1) Initial stage: Conduct periodontal assessment and oral hygiene education and guidance for the patient;

[0032] Specifically, the periodontal assessment is the foundation of secondary restoration, which can clarify the patient's periodontal tissue health status (such as probing depth, bleeding index, etc.), the amount of remaining tooth tissue and bone condition, and determine whether the clinical indications for secondary restoration are met; the oral hygiene education and guidance can improve the patient's understanding of postoperative care, reduce the risk of peri-restorative inflammation caused by plaque accumulation, and provide a guarantee for the subsequent treatment effect.

[0033] Step (2) Surgical preparation stage: Remove the original restoration, make an incision in the gingival sulcus and a vertical relaxation incision, open the full-thickness flap and remove residual tissue to expose the surgical area, determine the bony landmarks and trim the labial bone margin to form a symmetrical bone margin curve, use the vertical preparation method to re-prepare the tooth, scan the data of the trimmed alveolar bone, prepared tooth and other teeth, gingiva and occlusion, and scan the complete data of the intraoral cavity again after the surgical area is sutured.

[0034] Specifically, removing the original restoration eliminates obstacles that obstruct the field of vision, exposing the diseased area and healthy tooth tissue; incision and flap procedures fully expose the bone margin and root morphology, facilitating precise trimming; trimming the labial bone margin to form a symmetrical curve is to reconstruct a hard tissue morphology that conforms to biological principles, providing structural guidance for soft tissue healing; vertical preparation can preserve more healthy tooth tissue and increase dentin shoulder; scanning data can obtain three-dimensional information on oral hard and soft tissues and occlusal relationships, providing a precise basis for restoration design; secondary scanning can capture the soft tissue repositioning state after suturing, ensuring the compatibility of the restoration with the intraoral environment.

[0035] Step (3) Technician's processing stage: Receive scan data and check its integrity, perform data design to confirm parameters such as edge line position and placement path direction. After the doctor confirms the plan, digitally cut the zirconia crown, and then perform sintering, cooling, grinding and shaping, glazing and polishing.

[0036] Specifically, checking data integrity can avoid design errors in restorations due to missing or deformed data; confirming parameters such as edge lines and placement paths is key to ensuring a tight fit and smooth placement of the restoration edges; digital processing enables high-precision cutting through computer control, and combined with the biocompatibility and mechanical properties of zirconia, restorations that meet design requirements can be quickly produced; sintering and surface treatment can optimize the physicochemical properties of zirconia, improving the strength and aesthetics of the restoration.

[0037] Step (4) Immediate tooth fitting stage: Try on the zirconia restoration, check the position, margins, etc., and then perform intraoral bonding. Remove the sutures and place the rubber camphor. After removing the excess adhesive, reposition the tooth and suture it in place. Check and adjust the bite.

[0038] Specifically, trial fitting can verify the placement accuracy, marginal fit, and proximal relationships of the restoration, avoiding the impact of design errors on the restoration effect; intraoral bonding can fix the restoration to the prepared tooth, and rubber camphor can isolate saliva contamination and ensure bonding quality; removing excess bonding agent can prevent irritation of the gingival tissue and inflammation; adjusting the occlusion can avoid occlusal trauma and reduce the risk of restoration fracture or tooth damage.

[0039] Step (5) Postoperative follow-up stage: Postoperative follow-up examinations are conducted periodically, and relevant indicators are recorded;

[0040] Specifically, regular follow-up examinations can dynamically monitor postoperative tissue healing (such as gingival morphology, probing indicators, etc.) and the condition of the restoration (such as loosening, damage, etc.), promptly detect and treat complications (such as inflammation, malocclusion), assess the long-term stability of the restoration effect, and provide a basis for subsequent maintenance or adjustment.

[0041] In summary, the surgical preparation stage utilizes biological reshaping (BS) to rapidly establish hard tissue morphology that meets healing requirements, coupled with digital scanning to directly acquire precise hard tissue data; the laboratory stage leverages digital processing technology based on biocompatible materials (zirconia) (completing design, cutting, sintering, and other processes within 12 hours) to achieve rapid fabrication of the restoration; the immediate placement stage reduces placement obstacles through biologically compliant bonding methods (such as selecting self-curing materials with good flowability). The entire process eliminates the need to wait for the long-term stabilization period of periodontal tissues in traditional treatments, significantly reducing chairside time, number of treatments, and total treatment duration for patients.

[0042] Furthermore, in step (2), the tooth is re-prepared using a vertical preparation method and a German BOPT bur set to obtain a higher dentin shoulder and correct the asymmetrical long axis of the tooth, thereby increasing the interdental distance.

[0043] Specifically, this step involves vertical tooth cutting (rather than traditional horizontal shoulder preparation) combined with a specialized bur set to refine the tooth morphology. For example, using diamond burs with a taper of 5-8° from the German BOPT bur set, irregular tooth structure is first removed with a coarse bur of 100-120μm, and then the surface is refined with a fine bur of 20-30μm, ultimately resulting in a highly polished vertical prepared surface. Its purpose is to preserve more dentin shoulder (usually ≥1.5mm), enhancing the tooth's fracture resistance; at the same time, it corrects asymmetrical tooth long axis, increases the distance between adjacent roots, creates space for the growth of new gingival papillae, and improves aesthetics.

[0044] Furthermore, in step (2), the skeletal markers include the location of the cementoenamel junction and the alveolar crest, and the labial skeletal margin is trimmed to the position 2mm apical to the labial CEJ.

[0045] Specifically, this step involves using clinical examination or imaging to determine the cementoenamel junction (CEJ, the boundary between enamel and cementum) and the alveolar ridge crest (the coronal edge of the alveolar bone) as reference points, and then reshaping the labial bone margin to 2mm apical to the CEJ. For example, the CEJ position is located by periodontal probing combined with CBCT imaging, and bone trimming instruments are used to grind the labial bone margin to a predetermined depth, forming a continuous and symmetrical bone margin curve. Its purpose is to ensure that the bone margin position conforms to the biological width (usually 2mm, including 1mm of junctional epithelium and 1mm of connective tissue), to avoid the restoration invading periodontal tissues, to guide the gingival tissue to heal naturally along the trimmed bone margin, and to maintain periodontal health.

[0046] Furthermore, in step (3), the data types received by the technical room include STL, DCM, and PLY files. The processing time is about 12 hours, of which the time for digital cutting, sintering and cooling, and morphological trimming, glazing and dyeing is about 6 hours.

[0047] Specifically, this step involves the dental laboratory receiving the 3D data files generated from the oral scan (STL is a general format for 3D models, DCM is a medical image format, and PLY is a point cloud data format) and completing the fabrication of the restoration within 12 hours. The core processing steps (cutting, sintering, and finishing) take approximately 6 hours. For example, after receiving the STL format data from the patient's intraoral scan, the design is confirmed within 3 hours, and a five-axis cutting machine is used to cut the zirconia blank for 1.5 hours, followed by 2.5 hours of sintering and cooling (1350℃). Finally, the grinding, shaping, and glazing are completed in 1 hour. Its purpose is to ensure data compatibility and enable cross-device collaboration. By shortening the processing cycle (traditional processes require 3-7 days), it meets the demand for immediate restoration and reduces patient waiting time.

[0048] Furthermore, in step (3), the design of the zirconia crown conforms to the neck shape of BOPT, and the neck is highly polished without decorative porcelain or glaze porcelain;

[0049] Specifically, this step refers to the design of the neck (the area in contact with the gingiva) of the zirconia crown following the principles of Bio-Guided Preparation Technique (BOPT). This means that the neck shape conforms to the gingival sulcus anatomy, and the surface is polished without adding any additional porcelain veneer or enamel layer. For example, the neck is designed as a smooth curved surface that extends 1 mm into the gingival sulcus and is polished with a diamond grinding head to a surface roughness of ≤0.05μm, directly preserving the zirconia body. Its function is to prevent the porcelain veneer / enamel layer from falling off and irritating the gingiva. At the same time, the highly polished zirconia surface is conducive to the attachment of the binding epithelium, reducing plaque accumulation and maintaining healthy and stable gingiva.

[0050] Furthermore, in step (4), 3MLuting2 glass ionomer cement is used for intraoral bonding, and a bonding material with good fluidity and self-curing properties is selected.

[0051] Specifically, this step involves using 3M Liting2 glass ionomer cement as the bonding medium, utilizing its fluidity and self-curing properties to fix the restoration to the tooth. For example, the cement is evenly applied to the inner surface of the restoration and the prepared tooth surface, the restoration is gently pressed into place, and curing is completed within 3-5 minutes. Excess material can be removed with a probe. Its function is that the fluid material can fully fill the tiny gaps between the restoration and the tooth, ensuring marginal sealing; the self-curing properties can reduce the limitations of light curing operations and improve bonding efficiency and success rate.

[0052] Furthermore, in step (5), the follow-up period includes one week, one month, two months, three months, six months and twelve months after surgery, and the recorded indicators include PI, BOP, PPD, periapical radiographs and intraoral photographs;

[0053] Specifically, this step involves following up with patients at predetermined time points and evaluating the restoration effect using specific indicators. PI (plaque index) reflects oral hygiene, BOP (bleeding on probing) and PPD (probing depth) assess periodontal health, periapical radiographs observe alveolar bone changes, and intraoral photographs record soft tissue morphology and the appearance of the restoration. For example, BOP is checked one week post-surgery to assess early inflammatory response, PPD is measured at three months (normal should be ≤3mm) to assess periodontal stability, and periapical radiographs are used to compare changes in alveolar bone height at 12 months. Its purpose is to comprehensively assess the long-term stability of the restoration and the healing of periodontal tissues through multi-time-point and multi-dimensional monitoring, and to intervene promptly in any abnormalities.

[0054] Example 2

[0055] The core of the above-mentioned method for immediate secondary restoration of natural teeth lies in achieving "immediate restoration" through multi-stage collaboration. Among these, the efficiency and precision of the laboratory processing stage are crucial to the efficient implementation of the overall method. In this stage, the digital processing of zirconia restorations not only needs to match the hard tissue morphology data from the surgical preparation stage, but also needs to meet the requirements of biocompatibility and rapid fabrication. To further clarify the specific technical details of this processing procedure and ensure the operability of the overall method, the following example, Example 2, details the digital processing technology of zirconia restorations applicable to the above-mentioned restoration method.

[0056] A digital fabrication process for zirconia restorations includes the following steps:

[0057] S1 Data Acquisition: Scans and trims alveolar bone, hard tissue data of prepared teeth, and other intraoral teeth, gingiva, and occlusal data, generating STL, DCM, or PLY format files;

[0058] Specifically, this step aims to obtain precise data on the hard tissues of the oral cavity (alveolar bone, prepared tooth) and the surrounding soft tissue structures (tooth, gingiva) and occlusal relationships. This data forms the basis for subsequent prosthesis design and fabrication. Among these, hard tissue data (without gingival interference) ensures a precise match between the prosthesis and the biologically modified bone tissue and tooth morphology, while other intraoral data ensures coordination between the prosthesis and adjacent and opposing teeth. Generating STL, DCM, or PLY format files is to adapt to the data compatibility of the digital processing system, facilitating subsequent processing and design.

[0059] S2 Data Processing and Design: Check data integrity, confirm edge line position and placement path direction, set gap parameters, select tooth data, design restoration model conforming to BOPT cervical morphology, and have the dentist confirm compliance;

[0060] Specifically, this step is to conduct targeted design based on the collected data to ensure the clinical applicability of the restoration; checking the completeness of the data can avoid design errors caused by missing data; confirming parameters such as the position of the margin line and the direction of the insertion path is to ensure that the restoration margin is tight and the placement is smooth; setting the gap parameters can meet the functional requirements of the restoration; selecting tooth data and designing a model that conforms to the BOPT cervical morphology (the cervical morphology corresponding to the German Gumei BOPT bur set, which is beneficial to biocompatibility and gingival health) can take into account both the biological adaptability and aesthetic effect of the restoration; confirmation by the doctor further ensures that the design plan meets the clinical treatment needs.

[0061] S3 processing and fabrication: Based on the confirmed model, the zirconia blank is digitally cut, and the cut zirconia crown is sintered, naturally cooled, polished and shaped, glazed and polished at the neck. The total processing time is within 12 hours.

[0062] Specifically, this step is the core process of transforming the design model into a physical restoration; digital cutting can accurately reproduce the design shape and ensure the precision of the restoration; sintering can enhance the physical properties (strength, stability) of zirconia material, and natural cooling can prevent the material from cracking due to sudden temperature changes; grinding, shaping, glazing, and neck polishing (especially high polishing of the neck, without decorative porcelain and glaze porcelain) can improve the surface smoothness and biocompatibility of the restoration, which is conducive to the adhesion of the binding epithelium; the total processing time is controlled within 12 hours, which can achieve rapid production, support immediate restoration, and shorten the treatment cycle for patients.

[0063] Furthermore, in step S3, the digital cutting time is 1.5-2 hours, the total time for sintering and natural cooling is within 5 hours, and the time for grinding, shaping, glazing and neck polishing is about 1 hour.

[0064] Specifically, this step optimizes the balance between processing efficiency and quality by limiting the time range of each processing stage; digital cutting takes 1.5-2 hours, which ensures cutting accuracy while avoiding excessive time consumption; the total time for sintering and natural cooling is controlled within 5 hours, which ensures that the zirconia material is fully sintered to obtain the required properties and shortens the overall processing cycle; grinding and shaping take about 1 hour, which ensures surface quality (such as neck height polishing) while avoiding over-processing that affects efficiency; for example, in one case, digital cutting took 1.8 hours, sintering and cooling took 4.5 hours, and grinding and polishing took 50 minutes, for a total time of about 7 hours, which not only met the material performance requirements but also enabled the rapid fabrication of the restoration, providing a guarantee for wearing the tooth the next day.

[0065] Example 3

[0066] The goal of the aforementioned digital processing technology is to produce restorations that conform to the principles of bio-orthodontic guidance and are adapted to the healing patterns of oral tissues. The design and optimization of the process must ultimately be reflected in the specific structure of the restoration—the morphology, material properties, and surface treatment of the restoration directly affect its compatibility with periodontal tissues and the restorative effect. Therefore, the following example, through Example 3, details the specific structural features of the zirconia restoration produced using the above process. This structure, together with the restoration method of Example 1 and the processing technology of Example 2, constitutes a complete bio-orthodontic immediate restoration technology solution.

[0067] A zirconia restoration includes a crown body and a cervical structure, wherein the cervical structure is located 2 mm coronally to the alveolar ridge crest.

[0068] The location corresponds to the cementoenamel junction 2mm apical to the cementoenamel junction and extends 1mm into the gingival sulcus; the surface of the cervical structure has been highly polished and is free of decorative porcelain and enamel layers.

[0069] The core of the above structural design is to follow biological principles and adapt to the natural healing patterns of oral tissues. Specifically, the "alveolar ridge crest" refers to the top of the alveolar bone and is an important skeletal landmark of the periodontal tissues; the "cementoenamel junction (CEJ)" is the boundary between enamel and cementum, the natural boundary of the tooth structure; the "gingival sulcus" is the potential space between the gingiva and the tooth surface; the cervical structure is located 2mm coronally to the alveolar ridge crest and 2mm apically to the CEJ. This location meets the dimensional requirements of the supra-crissional attachment (STA) dimension, avoiding invasion of biological width and providing space for the healing of soft tissues such as the gingiva. Ample space guides tissue growth according to natural biological laws; the neck extends 1mm into the gingival sulcus, ensuring the stability of the restoration without excessively invading deep tissues and causing irritation; the neck surface is highly polished and free of enamel and porcelain enamel layers. Due to the excellent biocompatibility of zirconia, high polishing reduces the mechanical stimulation of the gingiva by surface roughness, which is conducive to the formation of stable attachment of the junctional epithelium on its surface; the absence of enamel and porcelain enamel avoids the chemical stimulation of periodontal tissues by additional materials, effectively reducing the risk of gingival inflammation. This design has been proven to maintain gingival health and stability in a 1-year follow-up.

[0070] Furthermore, the crown body is made of zirconium oxide material and sintered at high temperature of 1350-1450℃ for 2-3 hours.

[0071] This design aims to optimize the physical properties and processing efficiency of restorations by limiting the high-temperature sintering parameters of zirconia material. Zirconia material possesses excellent physical properties such as high strength and high wear resistance. High-temperature sintering can further improve its density and mechanical stability, ensuring that the restoration is not easily damaged during long-term use in the complex oral environment. Limiting the sintering temperature to 1350-1450℃ and the time to 2-3 hours ensures that the material is fully sintered to achieve the required strength, while also meeting the requirements of the overall processing cycle (total time ≤ 12 hours), avoiding the impact of excessively long sintering time on immediate restoration efficiency. For example, sintering at 1400℃ for 2.5 hours can make the flexural strength of zirconia material reach more than 1000MPa, while meeting the needs of rapid processing and reserving sufficient time for subsequent cooling, polishing and other steps, ensuring that the restoration can be completed and immediately placed within 12 hours.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for immediate secondary restoration of natural teeth, characterized in that, Includes the following steps: Step (1) Initial stage: Conduct periodontal assessment and oral hygiene education and guidance for the patient; Step (2) Surgical preparation stage: Remove the original restoration, make an incision in the gingival sulcus and a vertical relaxation incision, open the full-thickness flap and remove residual tissue to expose the surgical area, determine the bony landmarks and trim the labial bone margin to form a symmetrical bone margin curve, use the vertical preparation method to re-prepare the tooth, scan the data of the trimmed alveolar bone, prepared tooth and other teeth, gingiva and occlusion, and scan the complete data of the intraoral cavity again after the surgical area is sutured; Step (3) Technician's processing stage: Receive scan data and check its integrity, perform data design to confirm the edge line position and placement path direction parameters, after the doctor confirms the plan, digitally cut the zirconia crown, and then perform sintering, cooling, grinding and shaping, glazing and polishing. Step (4) Immediate tooth fitting stage: Try on the zirconia restoration, check the position, margins, etc., then perform intraoral bonding, remove the sutures and place the rubber camphor, remove the excess adhesive, then reposition the tooth and suture it in place, check and adjust the bite. Step (5) Postoperative follow-up stage: Postoperative follow-up examinations are conducted periodically, and relevant indicators are recorded.

2. The method for immediate secondary restoration of natural teeth according to claim 1, characterized in that, In step (2), the tooth is re-prepared using a vertical preparation method and a BOPT bur set to obtain a higher dentin shoulder and correct the asymmetrical long axis of the tooth, thereby increasing the interdental distance.

3. The method for immediate secondary restoration of natural teeth according to claim 1, characterized in that, In step (2), the skeletal markers include the location of the cementoenamel junction and the alveolar crest, and the labial skeletal margin is trimmed to the position 2mm apical to the labial CEJ.

4. The method for immediate secondary restoration of natural teeth according to claim 1, characterized in that, In step (3), the data types received by the technical room include STL, DCM, and PLY files. The processing time is about 12 hours, of which the time for digital cutting, sintering and cooling, and morphological finishing, glazing and dyeing is a total of 6 hours.

5. The method for immediate secondary restoration of natural teeth according to claim 1, characterized in that, In step (3), the design of the zirconia crown conforms to the neck shape of BOPT, and the neck is highly polished without decorative porcelain or glaze.

6. The method for immediate secondary restoration of natural teeth according to claim 1, characterized in that, In step (4), 3MLuting2 glass ionomer adhesive is used for intraoral bonding, and a bonding material with good fluidity and self-curing properties is selected.

7. The method for immediate secondary restoration of natural teeth according to claim 1, characterized in that, In step (5), the follow-up period includes one week, one month, two months, three months, six months and twelve months after surgery, and the recorded indicators include PI, BOP, PPD, periapical radiographs and intraoral photographs.

8. A digital processing technology for zirconia restorations, characterized in that, Includes the following steps: S1 Data Acquisition: Scans and trims alveolar bone, hard tissue data of prepared teeth, and other intraoral teeth, gingiva, and occlusal data, generating STL, DCM, or PLY format files; S2 Data Processing and Design: Check data integrity, confirm edge line position and placement path direction, set gap parameters, select tooth data, design restoration model conforming to BOPT cervical morphology, and have the dentist confirm compliance; S3 processing and fabrication: Based on the confirmed model, the zirconia blank is digitally cut, and the cut zirconia crown is sintered, naturally cooled, polished and shaped, glazed and polished at the neck. The total processing time is within 12 hours.

9. The digital processing technology for a zirconia restoration according to claim 8, characterized in that, In step S3, the digital cutting time is 1.5-2 hours, the total time for sintering and natural cooling is within 5 hours, and the time for grinding, shaping, glazing and neck polishing is about 1 hour.

10. A zirconium oxide restoration, characterized in that, It includes a crown body and a neck structure. The neck structure is located 2 mm coronally to the alveolar ridge crest, corresponding to 2 mm apically to the cementoenamel junction, and extends 1 mm into the gingival sulcus. The surface of the neck structure is highly polished and has no porcelain enamel or porcelain enamel layer.

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