Dental restoration manufacturing method based on prefabricated teeth and CADCAM technology

Abstract

The invention provides a dental restoration manufacturing method based on prefabricated teeth and a CADCAM technology, discloses a dental restoration manufacturing method based on prefabricated teeth and CAD / CAM equipment, and belongs to the technical field of dental restoration. The method comprises the following steps: pre-defining a processing tool with a positioning reference function; selecting prefabricated teeth based on an intraoral scanning model of a patient, and designing digital restoration denture data; generating three-dimensional data (the cavity is obtained by normal inversion of the surface of the false tooth) of the false tooth type box; the machining tool, the mold box and the repaired false tooth are combined, and a tissue surface cutting path is generated; manufacturing a real object type box through 3D printing or cutting; inserting a prefabricated tooth, injecting a gingival material, and solidifying to form a prosthesis blank; and the tissue surface is cut and machined through CAD / CAM equipment and is polished, and preparation is completed. The advantages of stable quality and low cost of prefabricated teeth and the advantages of high efficiency and accuracy of the CAD / CAM technology are integrated, the bonding accuracy error is avoided, the personalized adaptability is high, the method does not depend on the manual skill of technicians, batch production can be achieved, and the prepared prosthesis is accurate in shape and natural in color and can meet the functional and aesthetic requirements of patients.

Description

Technical Field

[0001] This invention relates to the field of dental prosthesis technology, specifically to a method for fabricating dental prostheses based on prefabricated teeth and CADCAM technology. Background Technology

[0002] Dental prostheses must simultaneously meet requirements such as shape fit, aesthetic color, and durability to restore the patient's speech and chewing function and optimize facial aesthetics. Since teeth need the strength, wear resistance, and white base color required for chewing, and gums need to withstand mucosal pressure, support tooth function, and achieve an aesthetically pleasing pink base color, both are typically made of dissimilar materials and must achieve a tight, secure bond and a high-precision shape fit.

[0003] Existing methods for making dentures can be mainly divided into three categories: Traditional manual fabrication method: Prefabricated standard teeth are mass-produced by manufacturers, and technicians manually arrange the teeth, build and carve wax models of the gums, embed them, rinse off the wax, pour in resin base material, cure, and polish to complete the fabrication. This method relies on the cost advantage of prefabricated teeth, but the tooth arrangement design is complex, the amount of manual work is large, and it requires a high level of experience and skill from the technician.

[0004] CAD / CAM Separate Cutting and Bonding Method: Dental resin parts and gingival resin parts are machined separately, and then bonded together after allowing for the required adhesive thickness. While digital design improves efficiency, it suffers from high cutting costs, limited material color options, and susceptibility to precision errors during the bonding process.

[0005] CAD / CAM integrated machining method: This method uses a two-color resin disc (white tooth material + pink gum material) and integrates CAD design with CAM milling for integrated molding. This method is highly efficient, has no loss of bonding precision, and does not rely on manual skills. However, the wave pattern of the two-color disc has limited adaptability to individual patient needs, and the material color is limited, resulting in high cutting costs.

[0006] In summary, existing methods cannot simultaneously achieve the advantages of prefabricated teeth in terms of quality and cost, as well as the advantages of CAD / CAM technology in terms of efficiency and precision. There is an urgent need for a new manufacturing method to solve the above-mentioned technical pain points. Summary of the Invention

[0007] The purpose of this invention is to provide a method for fabricating dental prostheses based on prefabricated teeth and CAD / CAM equipment, thereby integrating the advantages of stable quality and low cost of prefabricated teeth with the advantages of efficient design and precise processing of CAD / CAM technology. This enables the mass production of heterogeneous material prostheses without relying on the manual skills of technicians, while ensuring the fitting accuracy and aesthetics of the prosthesis.

[0008] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for fabricating dental restorations based on prefabricated teeth and CAD / CAM technology, the method comprising the following steps: (1) Predefined machining fixture, which has clamping and fixing functions and machining reference provision functions, including a platform reference surface in the height direction (Z-axis) and a fixing surface in the horizontal direction (XOY coordinate), and has anti-offset and anti-rotation capabilities; (2) Based on the intraoral scanning model and jaw position relationship, prefabricated teeth were selected, and digital prosthetic data with annotated tissue surfaces were designed; (3) Based on the digital restoration denture in step (2), generate three-dimensional data of the denture box. The cavity of the box is obtained by reversing the design of the denture surface, containing the precise tooth occlusal surface and gingival surface morphology. The box generation algorithm ensures the removal of undercut restrictions for prefabricated tooth insertion and retains the entire gingival surface morphology except for the tissue surface. (4) Adjust the orientation of the denture box to avoid cutting interference, strictly register the data of the box and the prosthesis, and then merge the machining fixture, the three-dimensional data of the box and the data of the prosthesis; using the XYZ reference plane of the box as the positioning reference, extract the spatial information from the tissue surface of the prosthesis along the positive Z-axis to the highest position of the tooling, and generate the milling path data of the tissue surface. (5) A physical model box is made using 3D printing or cutting equipment. The model box has an XYZ direction reference plane, which is compatible with the fixture of the CAD / CAM equipment. (6) Insert the prefabricated tooth selected in step (2) into the physical model box, inject the gingival material, and after the gingival material solidifies, the prefabricated tooth is tightly bonded to the gingival material to form a denture restoration blank. (7) The denture prosthesis blank is clamped onto the cutting machine, and the cutting path data generated in step (4) is executed to cut and process the tissue surface morphology of the denture prosthesis. The mold box part is removed and polished to complete the preparation of the dental prosthesis.

[0009] Preferably, the prefabricated teeth are standardized prefabricated tooth products with preset tooth shapes and layered colors.

[0010] Preferably, the gingival material is a pink resin base material, and the pre-made teeth are predominantly white, forming a heterogeneous material combination with the gingival material.

[0011] Preferably, in step (5), the 3D printing material for making the physical box is photosensitive resin, PLA or ABS, and the cutting equipment is a CAD / CAM milling machine.

[0012] Preferably, in step (6), after injecting the gingival material, heating and pressurizing are used to promote solidification, thereby ensuring the bonding strength between the pre-made tooth and the gingival material.

[0013] Preferably, after the processing fixture is combined with the denture mold, the restoration blank is accurately positioned on the CAD / CAM equipment through the XYZ direction reference plane.

[0014] In a second aspect, the present invention also provides a dental prosthesis manufactured using the method described above, the prosthesis comprising a prefabricated tooth and an integrally formed gingival structure, the prefabricated tooth being tightly bonded to the gingival material, and the tissue surface morphology of the prosthesis being precisely adapted to the patient's oral tissue.

[0015] Compared with the prior art, the beneficial effects of the present invention are: It combines multiple advantages: it not only leverages the stable quality, natural and beautiful layered colors, and low production cost of prefabricated teeth, but also integrates the advantages of CAD / CAM technology in digital design, high processing precision, and independence from the manual skills of technicians, thus overcoming the single-method shortcomings of existing methods.

[0016] High fitting accuracy: The normal reversal design of the mold box ensures the accuracy of the gingival surface morphology. The integration of the machining tooling and the mold box as a reference achieves precise positioning during the cutting process, avoiding the accuracy error caused by separate bonding. The integrated molding effect is better than the traditional bonding process.

[0017] Highly personalized and adaptable: Based on the patient's intraoral scanning model and jaw position relationship design, the selection of prefabricated teeth (including shape and material) and gingival material injection are both tailored to the individual needs of the patient, overcoming the problem of limited shape adaptability in the integrated processing of dual-color discs.

[0018] High production efficiency and mass production capability: Digital design and automated machining reduce manual operations, allowing for mass production of molds to meet the personalized needs of different patients and significantly improve production efficiency.

[0019] Cost-controllable: No need for a dedicated two-color resin disc, the cost advantage of mass production of prefabricated teeth combined with the low-cost production of mold boxes (3D printing or simple cutting) reduces the overall processing cost, and the choice of material colors is more flexible. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the machining tooling structure; Figure 2 Schematic diagram of a digitally restored denture model (with tissue surfaces marked); Figure 3 A schematic diagram of the tissue surface of a digitally restored denture; Figure 4 A schematic diagram of a three-dimensional data model of a digitally restored denture box; Figure 5 This is a schematic diagram showing the combined data of the repair denture mold and the machining tooling. Detailed Implementation

[0021] When fabricating dental restorations, it is necessary to pay attention to meeting requirements in terms of shape, color, stress resistance, and durability, so as to achieve or approach the effect of natural teeth as closely as possible, allowing patients to naturally perform speech, chewing, and swallowing functions, while also shaping the patient's aesthetic appearance.

[0022] Dental restorations that integrate teeth and gums, also known as prostheses, require different materials for the teeth. The teeth need the necessary jawline shape, strength, and wear resistance for chewing, and for aesthetic purposes, white is the primary color. The gums need to withstand mucosal pressure and support the teeth, while also being as small and thin as possible to reduce the feeling of a foreign body in the mouth; for aesthetic purposes, pink is the primary color. Therefore, the teeth and gums are made of different materials, and the two materials must be tightly and firmly bonded together, ensuring the accuracy of the resulting shape, to create a qualified prosthetic restoration.

[0023] For a long time, teeth have been made into prefabricated standard teeth by specialized dental manufacturers. The process involves first designing a standard tooth shape, then making a mold for each tooth, using the mold for mass casting, and further surface treatment and staining to mass-produce standard tooth products. The process for making denture restorations is as follows: First, the technician arranges one or more prefabricated teeth to form the required dentition based on the patient's dental mold and intraoral jaw relationship (standard tooth roots usually have some excess material, which needs to be ground off if interference occurs during the arrangement process); then, wax patterns are used to build and sculpt the gums; next, the wax pattern is embedded in plaster (boxed), heated to remove the wax (wax removal), then pink resin base material is filled in, heated and pressurized to cure; finally, the box is opened, the denture is removed, and it is finely polished.

[0024] With the advent of CAD / CAM systems, milling machining methods have also emerged, specifically divided into two types: separate cutting and bonding / merging, and integrated machining. In the CAD / CAM separate cutting and bonding / merging method, many denture material manufacturers provide separate dental resin discs and gingival resin discs. The designed teeth and gingiva are cut and machined separately, leaving room for adhesive thickness, and then the teeth and gingiva are bonded together to form a complete denture. CAD / CAM integrated machining, represented by Ivoire, has proposed a restoration fabrication method based on a two-color disc. This method fuses white dental material and pink gingival material into a single resin disc. The pink material has a pre-formed scalloped wave shape to construct the gingival margin. The fabrication process involves first designing the denture (including teeth and gingiva) using CAD software, then aligning the gingival margin line of the denture with the wave shape of the resin disc, further generating CAM machining data for the denture, and finally mounting the two-color resin disc onto a milling machine for milling.

[0025] Precast standard teeth have advantages such as diverse tooth shapes and materials, layered colors for a more natural and aesthetically pleasing appearance, high maturity, and low processing costs. However, their disadvantages include complex actual tooth arrangement design and fabrication techniques, high skill requirements for technicians, and a large amount of manual work. The CAD / CAM separate cutting and bonding method has the advantage of improved efficiency due to digital design, but disadvantages include high cutting costs, limited material color options, and potential precision errors during bonding. The CAD / CAM integrated processing method has the advantages of improved efficiency due to digital design, integrated molding without loss of precision during bonding, and no reliance on technician manual skills. However, disadvantages include limited adaptability of dual-color wavy patterns to individual patient needs, limited material color options, and high cutting costs.

[0026] This invention provides a method for fabricating dental restorations. In an exemplary embodiment, the specific steps of the method are as follows: Predefined machining fixture: Design a machining fixture with clamping and fixing functions and a machining reference. The fixture includes a platform reference surface in the height direction (Z-axis) and a fixing surface in the horizontal direction (XOY coordinates) to provide a precise positioning reference for subsequent machining.

[0027] Digital prosthetic design: Based on the patient's intraoral scanning model, jaw relationship data, and the requirements for the shape, material and color of the prosthesis, suitable prefabricated teeth are selected, and a complete digital prosthetic model is designed using CAD software, with clear marking of the tissue surface of the prosthesis (the surface in contact with oral tissues).

[0028] 3D Data Generation of Dental Cavity: Based on the digital prosthesis model, the 3D data of the denture cavity is generated using a normal inversion algorithm. The cavity of the cavity accurately replicates the occlusal and gingival surface morphology of the prosthesis. At the same time, algorithmic optimization removes undercuts that restrict the insertion of prefabricated teeth, ensuring smooth insertion and complete preservation of the gingival surface morphology except for the tissue surface.

[0029] Machining datum integration and cutting path generation: Adjust the spatial orientation of the denture mold box to avoid interference between the equipment and the workpiece during subsequent cutting processes; merge the 3D data of the machining fixture and the denture mold box, and adapt the XYZ directional datum plane of the mold box to the CAD / CAM equipment fixture; strictly register the mold box and prosthesis data, and then merge the machining fixture, mold box 3D data and prosthesis data; using the XYZ datum plane of the mold box as the positioning datum, extract the spatial information extending from the tissue surface of the prosthesis along the positive Z-axis to the highest position of the top of the fixture, and generate the milling path data of the tissue surface.

[0030] Physical mold box fabrication: Using 3D printing technology (printing materials can include photosensitive resin, PLA, ABS, etc.) or cutting equipment (such as CAD / CAM milling machines), a physical mold box is fabricated based on the mold box's 3D data. The XYZ direction reference planes of the physical mold box must be precisely matched with the fixtures of the CAD / CAM equipment to ensure subsequent clamping and positioning accuracy.

[0031] Preparation of prosthesis blank: The prefabricated teeth selected in the above steps are precisely inserted into the corresponding cavity of the physical mold box according to the design position. Pink gingival material (such as resin base material) is injected into the mold box. Heating and pressurizing can be used to promote the solidification of the gingival material, so that the prefabricated teeth and gingival material can be tightly bonded under the constraint of the mold box, forming a prosthesis blank containing the mold box, prefabricated teeth and gingival material.

[0032] Machining and Finished Product Preparation: The denture prosthesis blank is clamped into a CAD / CAM cutting device using a machining fixture. Based on the cutting path data generated in the above steps, the tissue surface morphology of the prosthesis is precisely machined to perfectly fit the patient's oral tissue. After machining, the mold box is removed, and the surface of the prosthesis is simply polished to obtain the final dental prosthesis.

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Example 1: Fabrication of Dental Prostheses Machining tooling design: such as Figure 1 As shown, the tooling is designed and manufactured using CAD software. The tooling includes a 100mm diameter disc-shaped platform reference surface (height, Z-axis direction) and a cutting surface fixed surface perpendicular to the platform (XOY plane, to ensure that the tooling does not shift or rotate), ensuring clamping stability and positioning accuracy.

[0037] Digital design: such as Figure 2 As shown, an intraoral scanner was used to acquire a scanning model of the patient's maxillary edentulous area and data on the jaw position relationship between the maxilla and mandible, which was then imported into CAD software. A prefabricated standard tooth (with a natural, layered white tone that conforms to the patient's dentition morphology) was selected to design a digital prosthesis model including the prefabricated tooth and corresponding gingival structure, clearly marking the tissue surfaces of the prosthesis, such as... Figure 3 As shown.

[0038] 3D Data Generation of Dental Cavity: Based on a digital prosthetic model, a normal inversion algorithm is used to generate 3D data of the prosthetic cavity. The cavity depth is determined based on this data, and the occlusal and gingival surface morphology of the prosthesis is replicated on the inner wall. An algorithm is used to remove undercuts along the insertion path of the prefabricated tooth, ensuring smooth insertion. Figure 4 As shown.

[0039] Reference integration and cutting path generation: Adjust the shape box posture to ensure that the cutting direction avoids the tooling interference area; strictly register the shape box and prosthesis data, and then, as shown in the figure, merge the machining tooling, shape box 3D data and prosthesis data; using the shape box XYZ reference plane as the positioning reference, extract the spatial information from the prosthesis tissue surface along the positive Z-axis to the highest position of the tooling top, and generate the milling path data of the tissue surface.

[0040] Physical model box fabrication: The physical model box is printed using a photosensitive resin 3D printer with a printing accuracy of ±0.03mm. The gap between the reference plane of the model box in the XYZ direction and the CAD / CAM equipment fixture is ≤0.01mm.

[0041] Preparation of restoration blanks: Insert three precast teeth into the physical mold box according to the design position, inject pink resin base material, and place it in a heated and pressurized curing oven (temperature 70℃, pressure 0.3MPa, curing time 30min). After the resin is completely solidified, the precast teeth are tightly bonded to the resin gingiva to form the restoration blank.

[0042] Machining and Finished Product: The restoration blank is clamped onto a CAD / CAM milling machine using a machining fixture. The cutting path data is executed to precisely cut the tissue surface to the designed shape (tissue surface roughness Ra≤0.8μm). The mold box part is removed, and the surface of the restoration is lightly polished with a polishing tool to obtain a dental restoration that fits the patient's oral cavity.

[0043] Tests showed that the bonding strength between the tooth and gum of the restoration was ≥2.5MPa, the gap between the tissue surface and the patient's oral tissue was ≤0.1mm, and the color was natural and harmonious, meeting the requirements of chewing function and aesthetics.

[0044] This embodiment illustrates the design and fabrication process of maxillary dentures using schematic diagrams. The design and fabrication process of mandibular dentures is exactly the same. In addition, as long as the size of the processing fixture allows, multiple dentures can be fabricated on the same fixture according to the aforementioned process.

[0045] Any aspects of this invention not described in detail are well-known to those skilled in the art.

[0046] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications and equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for fabricating dental restorations based on prefabricated teeth and CAD / CAM technology, characterized in that, Includes the following steps: (1) A predefined machining fixture, which has clamping and fixing functions and machining reference provision functions, including a platform reference surface in the height direction and a fixing surface in the horizontal direction; (2) Based on the intraoral scanning model and jaw position relationship, prefabricated teeth were selected, and digital prosthetic data with annotated tissue surfaces were designed; (3) Based on the digital restoration denture in step (2), generate three-dimensional data of the denture box. The cavity of the box is obtained by reversing the design of the denture surface, containing the precise tooth occlusal surface and gingival surface morphology. The box generation algorithm ensures the removal of undercut restrictions for prefabricated tooth insertion and retains the entire gingival surface morphology except for the tissue surface. (4) Adjust the orientation of the denture mold box to avoid cutting interference, strictly register the mold box and the restoration denture data, and then merge the machining tooling, mold box three-dimensional data and restoration denture data; Using the XYZ reference plane of the mold box as the positioning reference, the spatial information extending from the tissue surface of the restored denture along the positive Z-axis to the highest position of the tooling is extracted to generate the milling path data of the tissue surface; (5) A physical model box is made using 3D printing or cutting equipment. The model box has an XYZ direction reference plane, which is compatible with the fixture of the CAD / CAM equipment. (6) Insert the prefabricated tooth selected in step (2) into the physical model box, inject the gingival material, and after the gingival material solidifies, the prefabricated tooth is tightly bonded to the gingival material to form a denture restoration blank. (7) The denture prosthesis blank is clamped onto the cutting machine, and the cutting path data generated in step (4) is executed to cut and process the tissue surface morphology of the denture prosthesis. The mold box part is removed and polished to complete the preparation of the dental prosthesis.

2. The manufacturing method according to claim 1, characterized in that, The prefabricated teeth are standardized prefabricated tooth products with preset tooth shapes and layered colors.

3. The manufacturing method according to claim 1, characterized in that, The gingival material is a pink resin base material, and the pre-made teeth are predominantly white, forming a heterogeneous material combination with the gingival material.

4. The manufacturing method according to claim 1, characterized in that, In step (5), the 3D printing materials used to make the physical box are commonly used 3D printing molding materials such as photosensitive resin, PLA, PHA and ABS, and the cutting equipment is a CAD / CAM milling machine.

5. The manufacturing method according to claim 1, characterized in that, In step (6), after injecting the gingival material, the bonding strength between the prefabricated tooth and the gingival material should be ensured.

6. The manufacturing method according to claim 1, characterized in that, After the processing fixture is combined with the denture mold, the restoration blank is accurately positioned on the CAD / CAM equipment through the XYZ direction reference plane.

7. A dental prosthesis, manufactured using the method described in any one of claims 1-6, characterized in that, The restoration comprises prefabricated teeth and an integrally formed gingival structure. The prefabricated teeth are tightly bonded to the gingival material, and the tissue surface morphology of the restoration is precisely adapted to the patient's oral tissue.

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