CN106037966A - Dental restoration CAD (computer aided design)/metal 3D automatic processing method - Google Patents

Abstract

The invention discloses a brand-new automatic processing method for oral prosthesis. The method adopts a composite system composed of optical scanning, computer-aided design system, CAD auxiliary system and selective laser cladding machine to process oral prosthesis. The combination of advanced oral CAD system and metal 3D printing technology can achieve rapid and individualized production of metal dental restorations, which can change the traditional production method of implants and their superstructures, from CNC cutting to metal 3D printing, with extremely high processing efficiency. Greatly improved, it can also realize personalized production. If necessary, it can also be organically combined with the two processing methods of CNC cutting auxiliary processing. How its superstructure is made.

Description

A CAD/metal 3D automatic processing method for dental restorations

technical field

The invention belongs to the technical field of oral restorations, and in particular relates to a new CAD/metal 3D automatic processing method for oral restorations. The method combines the existing oral CAD system with metal 3D printing technology to achieve rapid and personalized metal oral cavity manufacturing. Restoration.

Background technique

Computer-aided design (CAD) and computer-aided manufacture (CAM) technologies integrate multidisciplinary knowledge and technologies such as mathematics, optics, electronics, computer image recognition and processing, automatic control and automatic processing, etc. It was widely used in industrial automation and aerospace in the 1970s. In 1983, the first dental CAD/CAM system prototype developed by France Duret came out in France; in 1985, at the French International Dental Academic Conference, Professor Duret used this equipment to produce the first posterior porcelain crown and successfully used it on patients Stomatology, making the use of CAD/CAM in the field of stomatology a reality. After entering the 1990s, with the further development of modern optoelectronic technology, computer technology, image analysis and processing technology, more and more dental CAD/CAM systems came out. At present, more than 10 kinds of CAD/CAM systems have come out, which can make inlays, veneers, full crowns, partial crowns, fixed bridges, implant bridges, etc. However, removable partial dentures and complete dentures are still in the research stage, and there is no mature system. Dental CAD/CAM system usually consists of three subsystems: data acquisition (digital impression), computer-aided design (CAD), and computer-aided production (CAM). A new technology of oral restoration began to take shape, and the CAD/CAM system brought the restoration of oral cavity into the modern high-tech field.

1. Main CAD/CAM system

In the current commercial dental CAD/CAM system, CNC milling machine is one of the important components. The machining of the prosthesis is controlled by a CNC milling machine to remove excess material to obtain a prosthesis that meets the requirements of shape, size and surface roughness. This technology essentially belongs to the category of material removal, which is called "subtraction" in this field.

1.1 Cerec system

The Cerec system was developed and gradually perfected by the Dental Department of Siemens AG (SIEMENS), which is now the German SIRONA Dental Equipment Co., Ltd. Its product series include CerecⅠ, CerecⅡ and CerecⅢ and Cerec in Lab. CerecⅢ is a CerecⅢ system born in 2000. This system is based on the Windows platform. The cutting system and the image acquisition system work independently. The software system has also been greatly improved, so that the CerecⅢ system can make inlays, onlays and veneers , Partial and Full Crowns. However, the CerecⅢ software system can only be designed on a plane, and it is difficult to display the overall shape of the restoration. In March 2003, the Cerec 3D system was exhibited for the first time at the Hinman Dental Conference in Atlanta, USA. It can introduce multi-dimensional perspectives when designing restorations, and can intuitively evaluate the shape of restorations and abutment teeth from a three-dimensional perspective. The Cerec 3D software system has added 3D design software such as FrameWork to realize the restoration of all-ceramic fixed bridges. In 2002, Sirona launched the Cerec in Lab system, which is specially designed for laboratories. It uses a laser scanning system to collect dental and jaw data. The restoration is made faster, has a wider range of applications, and can use higher-strength secondary Alumina, zirconia ceramic materials.

1.2 Celay system

The Celay system was designed by the Zurich School of Dentistry and exhibited for the first time in Munich in 1990, and is now produced by the Swiss company Mikroma. This system is not a CAD/CAM system in the full sense. Its principle is similar to a small key duplicating machine. It consists of two parts, a contact sensor and a micro milling machine. Hardness wax or resin restoration surface shape data, and the data is transmitted to the milling machine at the same time, and the porcelain restoration is processed synchronously. The system is simple in composition and low in automation. When working, a temporary restoration must be made in the mouth or on the model as an information source for obtaining data. The Celay system mainly uses alumina machinable ceramics to process inlays or onlays with occlusal surface shapes, and can also process full crowns or base crowns of fixed bridges.

1.3 Procera system

The Procera system is a Swedish system that was introduced to the market by Nobel Biocare in 1993. Now, the system uses the Procera Piccolo or the more advanced Procera Forte scanner to collect data on the dental model, and the physician uses the Procera Lofrwore 2.0 software to design the restoration. After completion, the data is sent to the 4 production centers designated by the Procera system through the Internet (Stockholm, Sweden; Fair Lawn, NJ, USA; Karlskoga, Sweden; Tokyo, Japan) for machining of the restorations. The processing center can directly process the final zirconia and alumina all-ceramic crowns and bridges according to the doctor's requirements, or only process the zirconia and alumina substrates to be mailed back and then be decorated with porcelain on the surface. The Procera system can not only be used to make natural tooth crowns, but also can be used in the field of implantology. The Procera system can cut and make single tooth abutments of pure titanium or zirconia, which can personalize the shape and shape of the height, angle and edge line of the abutment; the Procera system can also cut and make implant bridges of pure titanium or zirconia , which can provide up to 14 units of implant bridges, has excellent biocompatibility, excellent strength and aesthetic effects.

1.4 Cercon system

The Cercon system uses the Cercon Eye Scanner 3D laser to scan the data on the dental model, transmits it to the Cercon Art CAD part to design the restoration, and then transmits the designed information to the Cercon Brain part to cut the restoration or pass the information through the Internet Transfer to the production center in York for processing and production of the restoration. Therefore, for some small dental clinics or technical centers, you can only purchase the Cercon ArtCAD part of the Cercon system (which already includes the Cercon Eye Scanner scanner), thereby reducing costs. Cercon Art CAD can finely design the edges and joints of the restoration. The Cercon system uses zirconia structural ceramics as the processing object, and can produce post cores, implant abutments, full crowns and fixed bridges.

1.5 Lava system

The Lava system was launched by 3M Company of the United States in 2002 and consists of Lava Scan, Lava CAD, Lava Form, LavaTherm and other parts. First, a non-contact 3D optical scanning system is used to collect data on the dental model. The doctor uses LavaDesign 4.0 software to design the restoration. After completion, the base crown is first obtained by cutting the pre-sintered zirconia ceramic block. On average, each unit crown needs 35 minute. After the cutting is completed, the crown base crown is completely sintered, and then the veneer porcelain is added on its surface. Compared with the Vita colorimetric system, Lava zirconia-based crowns have 7 color options, and veneer porcelain has 16 color options, so the restorations made by the Lava system have the color and light transmittance closest to natural teeth. This system is mainly suitable for It is suitable for the restoration of single crown and 3-4 unit fixed bridges of anterior and posterior teeth.

1.6 Everest system

The Everest system was introduced to the market in 2002 by the German company Kavo. The system consists of four components: Everest scan, Everest engine, Everest therm, and Everest elements. First, the Everest scan data scanning system (using a CCD camera) collects the data on the dental model, and the operator uses ENERGY CAD software to design the restoration in 3D, and then the CAM part is arranged on the five axes of X, Y, Z, A, and B. Machining the restoration. Therefore, the restorations made by the Everest system have good machining accuracy and clear anatomical structure. The Everest system can process a wide range of materials, including zirconia, alumina, pure titanium, glass ceramics, gold, resin, etc., and can be used to make implants, veneers, inlays, onlays, single crowns and fixed bridges.

1.7 Open System

The open system is an "assembled" CAD/CAM system that has appeared on the market in recent years. Its data acquisition system, CAD system, and CAM system can be assembled by different companies. There are two options for relatively mature open systems on the market:

1) 3Shape dental scanner + CAD software + German CNC lathe, which can process all brands of zirconia and plastics, without brand restrictions;

2) 3Shape dental scanner + CAD software + American 3D system wax-up machine, after making the wax-up, you can embed casting metal or make all-ceramic crowns.

Compared with other CAD/CAM systems, the advantage of the open system is that the materials that can be processed are more extensive and the production cost is lower.

2. CAD/CAM system for additive manufacturing

The inability of the above-mentioned CNC lathe to cut restorations with complex structures (such as hollow structures) and the waste of materials during the cutting process have become key problems that need to be solved urgently in the advanced manufacturing technology of dental restorations. Rapid prototyping technology, referred to as RP or RPM technology (Rapid Prototyping/Rapid Prototyping Manufacturing), is an advanced manufacturing technology developed in the late 1980s. This technology integrates advanced sciences such as computer-aided design (CAD), computer-aided manufacturing (CAM), computer numerical control (CNC), precision servo drive, laser and material science, and adopts the idea of discrete-layer stacking, the basic idea Yes: Any three-dimensional part can be regarded as a superposition of many two-dimensional plane contours along a certain coordinate direction. However, RP technology cannot directly make metal restorations to meet the needs of oral restoration. In the late 1990s, the rapid manufacturing technology (Rapid Manufacturing, RM) established by the combination of RP technology and laser coating technology adopts the method of preset powder spreading or synchronous powder feeding, and the laser cladding and accumulating powder materials layer by layer to obtain a three-dimensional entity Component. The formed parts produced by it have excellent physical and chemical properties and are not limited by complex structures. Both RP technology and RM technology belong to additive production in essence, that is, "addition". In 2003, Gao Bo applied for the Chinese invention patent of "Laser Stereoscopic Forming Method for Oral Metal Restoration", which was authorized in 2005, ZL03134316.3. At present, the mainstream methods of 3D printing for metal restorations are SLM (selective laser melting) and EBM (Electron Beam Melting). for the fabrication of metal implants.

2.1 Application in fixed restoration

In 2004, Bennett used the MCP Realizer equipment based on SLM technology to make cobalt-chromium alloy and stainless steel base crowns, fixed crowns and fixed bridges respectively. The crowns were in good shape. In 2005, French scholar Nadine applied the Phenix SLM system developed by himself to design and manufacture a nickel-chromium alloy base crown. Color matching and edge fit.

2.2 Application in removable partial dentures

In 2006, Williams et al. made cobalt-chromium alloy brackets for removable partial dentures on the SLM Realizer 2 machine through CAD/CAM technology. In China, Wu Lin and others initially realized the computer-aided design of Ken's class II dentition defect model, and used laser rapid prototyping to process the resin mold of the removable partial denture bracket. In 2009, Zhu Senyang et al. carried out computer-aided design and fabrication of removable partial denture brackets for Ken's Class I dentition defects.

2.3 Application in complete dentures

The shape of complete dentures is complex, and the materials that make up dentures are diverse, and the research on CAD/CAM of complete dentures is relatively lagging behind. Gao Bo from the Fourth Military Medical University of the Chinese People's Liberation Army designed the upper half metal base denture through the Surfacer software, and used the laser three-dimensional forming technology to preliminarily process the upper half base. In 2008 and 2009, Gao Bo of the Fourth Military Medical University of the Chinese People's Liberation Army published a treatise on laser rapid prototyping for the manufacture of full dentures with maxillary pure titanium substrates. 133 to 136, and its suitability has been studied, and the clinical test results show that its production accuracy needs to be improved.

3. Limitation and development direction of traditional CAD/CAM in clinical application

The application of CAD/CAM technology in the field of oral cavity has greatly improved the restoration efficiency, shortened the treatment cycle of patients, reduced the pain of patients and reduced the labor intensity of technicians, which has made a revolutionary development in prosthodontics. However, there are still the following problems in the clinical application process: At present, CAD/CAM systems are mainly used in the field of fixed restorations, but not in removable partial dentures and complete dentures. The main reason is the inherent limitations of CAD/CAM systems in cutting. This not only leads to waste of materials, but also makes the types of prosthetics produced single, and composite prosthetics cannot be machined.

To sum up, if the metal 3D printing technology can replace the cutting manufacturing technology of the traditional CAD/CAM system, let’s call it the dental CAD/metal 3D printing system, it will be able to better expand the indications and restoration of dental restorations. body mass.

Contents of the invention

In view of the defects or deficiencies in the above-mentioned prior art, the purpose of the present invention is to provide a new oral restoration processing method, which combines the existing oral CAD system with metal 3D printing technology to achieve rapid and personalized production Metal dental restorations.

In order to realize above-mentioned task, the present invention takes following technical solution:

A CAD/metal 3D automatic processing method for dental restorations, characterized in that the method adopts a composite system composed of optical scanning, computer-aided design system, CAD auxiliary system and selective laser cladding machine to process oral restorations, specifically including the following step:

Step 1. Routinely complete the three-dimensional shape scanning of the patient's intraoral or extraoral plaster model and establish a data model consistent with the tooth loss in the oral cavity;

Step 2: According to the design principle of the oral restoration, the CAD auxiliary system is used to complete the configuration design and production of the oral restoration, and the output data format is the STL format compatible with the selective laser cladding machine;

Step 3: The selective laser cladding machine uses the metal powder material formed by SLM to discretize the CAD three-dimensional data model of the oral restoration obtained in step two into two-dimensional plane data, and process the two-dimensional plane profile data according to the preset order. Accumulate layer by layer, cladding and accumulating metal powder materials are formed to obtain metal dental restorations.

Step 4, baking plastic or porcelain on the metal dental prosthesis to complete the production of the dental prosthesis.

Among them, the selective laser cladding machine cladding accumulation metal powder material forming described in step 3 is to spread the metal powder material on the metal substrate in the vacuum inert gas processing chamber, and the thickness of a single layer of powder is based on different metal powder materials Depending on the characteristics and processing accuracy, the specific molding steps are as follows:

(1) Put the metal powder on the powder bed and heat up to a suitable temperature;

(2) After the step (1) is completed, the laser beam clads and shapes the metal powder according to the two-dimensional plane profile;

(3) After the step (2) is finished, carry out the second powder spreading, scrape the surface of the powder bed with a scraper, and then follow the sequence of steps (1) and (2) to carry out a new layer of single-pass cladding molding ; After repeated powder spreading and single-pass cladding molding, the unclad powder and supporting structure can be removed to obtain the metal oral restoration.

Said step 2 further includes: during the computer-aided design of the dental restoration, the CAD-assisted system designs a retention structure at the joint between the metal bracket and the artificial tooth that is conducive to promoting metal-ceramic bonding or baking-plastic bonding, and these retention structures include Position microbeads, retaining microspheres, or honeycomb structures that increase the bonding area.

The oral restorations include:

(1), personalized post and core, crown bridge, porcelain crown and bridge base, removable partial denture framework or complete denture base; or

(2) Individualized implants, bridges for implant superstructures, and individualized abutments.

The innovation of the oral restoration CAD/metal 3D automatic processing method of the present invention lies in:

1. Change the traditional manufacturing method of the implant and its upper structure, from CNC cutting to metal 3D printing processing, which greatly improves the processing efficiency, and can also realize personalized production. If necessary, it can also be combined with CNC cutting auxiliary processing. The processing methods are organically combined, and each takes its own advantages to achieve the perfect combination of metal 3D printing and CNC cutting, subverting the original production method of implants and their superstructures.

2. During the 3D printing process of the implant, an appropriate amount of silver ion powder can be mixed to achieve the purpose of antibacterial without affecting osseointegration.

3. In CAD design, design a special retention structure at the connection between the metal bracket and the artificial tooth, which is conducive to promoting metal-ceramic bonding or baking-plastic bonding: such as retention microbeads, retention microspheres, or increase the bonding area Honeycomb structure, etc., through metal 3D printing to produce a special structure of metal brackets that meet the design requirements, so as to improve the bonding force between plastic or ceramics and metal brackets while baking plastic or ceramics on metal brackets, and reduce the damage rate of ceramics or plastics , which is conducive to the long-term and stable normal function of the oral restoration.

4. The composite system composed of optical scanning, computer-aided design system, CAD auxiliary system and selective laser cladding machine in the method of the present invention can be placed on a mobile vehicle, such as a car or a boat, which is equivalent to a mobile denture Digital processing factory.

Description of drawings

Fig. 1 is the composite system block diagram that the optical scanning that the present invention adopts and computer-aided design system, CAD auxiliary system, selective laser cladding machine form;

Figure 2 is a structure diagram of a metal oral restoration prepared by taking the removable partial denture TC4 bracket as an example;

Figure 3 is a formal picture of the special structure at the connection between the metal bracket of the restoration and the ceramic or plastic;

Figure 4 is a picture of the removable partial denture TC4 metal bracket completed by metal 3D printing;

Figure 5 is a display picture of the partial special structure of the removable partial denture TC4 metal bracket;

Fig. 6 is a photo of porcelain or plastic baked on removable partial denture TC4 metal support frame;

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

detailed description

Referring to Fig. 1, the present invention provides a new oral restoration processing method, which uses a composite system composed of optical scanning, computer-aided design system, CAD auxiliary system and selective laser cladding machine to process oral restoration. The composite system consists of three parts. The first part is the optical scanning and computer-aided design system, which is used to complete the acquisition of the digital model of the oral restoration; the second part is the CAD auxiliary system of the oral restoration, which is used to complete the configuration of the oral restoration. Computer Aided Design. The third part is the miniaturized selective laser cladding machine, which plays the role of metal 3D printing, and builds up the CAD data of the designed oral restoration with metal powder cladding. Specifically include the following steps:

Step 1. Routinely complete the three-dimensional shape scanning of the patient's intraoral or extraoral plaster model and establish a data model consistent with the tooth loss in the oral cavity;

Step 2: According to the design principle of the oral restoration, the CAD auxiliary system is used to complete the configuration design and production of the oral restoration, and the output data format is the STL format compatible with the selective laser cladding machine;

Step 3: The selective laser cladding machine uses the metal powder material formed by SLM to discretize the CAD three-dimensional data model of the oral restoration obtained in step two into two-dimensional plane data, and process the two-dimensional plane profile data according to the preset order. Accumulate layer by layer, cladding and accumulating metal powder materials are formed to obtain metal dental restorations;

Step 4, baking plastic or porcelain on the metal dental prosthesis to complete the production of the dental prosthesis.

The metal dental restorations mentioned above include: 1. Personalized metal posts and cores, metal crowns and bridges, porcelain crowns and bridges bases, metal brackets for removable partial dentures, and metal bases for complete dentures;

2. Personalized implants, bridges for implant superstructures, personalized abutments, etc.;

Said step 2 further includes: during the computer-aided design of the dental prosthesis, the CAD-assisted system designs a retention structure at the joint between the metal bracket and the artificial tooth, which is conducive to promoting metal-ceramic bonding or baking-plastic bonding, and these retention structures include retention structures Microbeads, retaining microspheres, or a honeycomb structure that increases the bonding area to increase the bonding force between ceramics or plastics and metal stents.

The following is the detailed whole process of making a relatively complicated removable partial denture in an oral restoration given by the inventor:

1. Materials and equipment

1.1 Materials and equipment required for SLM

Selective laser cladding machine (EOSINT M280, EOS company, Germany);

TC4 powder, spherical powder, particle diameter 15-53 micron (Carpenter company, the U.S.);

Optical scanning and computer-aided design system (DWOS, Dental Wings Inc., Canada).

1.2 Other materials and equipment

Conte "Water Cube" silicone rubber impression material (Conte Dental Group, Switzerland);

Superhard gypsum (Hubei Beinuo Dental Materials Co., Ltd.).

1.3 Case selection and abutment preparation

A 56-year-old male patient with missing left maxillary premolars and first molars was unable to receive implants and fixed dentures. He voluntarily underwent traditional metal-supported removable partial dentures.

The design of the removable partial denture is shown in Figure 2. It is a tooth-supported removable partial denture. 13, 17, 23, and 27 are used as abutment teeth, and the occlusal rest is placed. The clasp is designed on the lip and buccal side, and the wide posterior palatal bar is a large connector. . Complete clinical abutment preparation.

1.4 Computer-aided design and 3D printing of removable partial denture framework

Two plaster casts of the patient's oral cavity were prepared, and one was made by the traditional lost-wax casting method and worn by the patient. Another way is to use the optical scanning and computer-aided design system to obtain the digital model of the plaster model, and use the removable partial denture design software of 3shape to complete the CAD design drawing of the removable partial denture TC4 bracket (Fig. 2). It should be emphasized that in 14 , 15, 16 The edentulous area was designed to design a special retention microbead structure to increase the bonding force (Figure 3), and then use this data to perform metal 3D printing on a selective laser cladding machine to produce a removable partial alloy denture TC4 bracket (Figure 4). Figure 5 shows the partial special structure of the removable partial denture TC4 metal bracket. The printing production parameters are 400W fiber laser, the thickness of single-layer powder coating is 60 microns, and the scanning path is linear filling + outer contour scanning.

In this embodiment, the selective laser cladding machine plays the role of metal 3D printing. Its cladding and accumulation of TC4 powder is formed in a vacuum inert gas processing chamber, and the TC4 powder material is spread on the metal substrate. According to the characteristics and processing accuracy of different metal powder materials, the specific forming steps are as follows:

(1) Put the metal powder (TC4 powder) on the powder bed and heat up to a suitable temperature;

(2) After the step (1) is completed, the laser beam clads and shapes the metal powder according to the two-dimensional plane profile;

(3) After the step (2) is finished, carry out the second powder spreading, scrape the surface of the powder bed with a scraper, and then follow the sequence of steps (1) and (2) to carry out a new layer of single-pass cladding molding ; After repeated powder spreading and single-pass cladding molding, remove the unclad powder and supporting structure, and then obtain the removable partial alloy TC4 bracket.

1.5 Removable partial alloy denture TC4 frame baked plastic or porcelain

Plastic or porcelain is baked on the special structure at the connection between the removable partial alloy denture TC4 bracket and the artificial tooth to complete the production of the oral restoration (Fig. 6).

It should be noted that the above embodiments are to help those skilled in the art to understand the present invention, the present invention is not limited to the above embodiments, according to the method of the present invention, can also be used for personalized post-core, crown and bridge, porcelain crown and bridge Base, removable partial denture bracket or complete denture base; or automatic processing of various oral restorations such as personalized implants, bridges of implant superstructures, and personalized abutments. During the implant 3D printing process, an appropriate amount of silver ion powder can be mixed to achieve the purpose of antibacterial without affecting osseointegration.

Of course, the composite system of optical scanning, computer-aided design system, CAD auxiliary system and selective laser cladding machine used in the method of the present invention can be placed on mobile vehicles, such as cars and boats, which is equivalent to a mobile denture Digital processing plants provide patients with more convenient services.

Claims (4)

1. A kind of dental prosthesis CAD/metal 3D automatic processing method, it is characterized in that, the method adopts optical scanning and computer-aided design system, CAD auxiliary system and selective laser cladding machine to form composite system to process oral prosthesis, specifically Include the following steps: Step 1. Routinely complete the three-dimensional shape scanning of the patient's intraoral or extraoral plaster model and establish a data model consistent with the tooth loss in the oral cavity; Step 2: According to the design principle of the oral restoration, the CAD auxiliary system is used to complete the configuration design and production of the oral restoration, and the output data format is the STL format compatible with the selective laser cladding machine; Step 3: The selective laser cladding machine uses the metal powder material formed by SLM to discretize the CAD three-dimensional data model of the oral restoration obtained in step two into two-dimensional plane data, and process the two-dimensional plane profile data according to the preset order. Accumulate layer by layer, cladding and accumulating metal powder materials are formed to obtain metal dental restorations; Step 4, baking plastic or porcelain on the metal dental prosthesis to complete the production of the dental prosthesis. 2. The method according to claim 1, wherein said oral restoration comprises: (1), personalized post and core, crown bridge, porcelain crown and bridge base, removable partial denture framework or complete denture base; or (2) Individualized implants, bridges for implant superstructures, and individualized abutments. 3. The method according to claim 1, characterized in that, the selective laser cladding machine described in step 3 cladding and accumulating metal powder material molding is in the vacuum inert gas processing chamber, the metal powder material is spread on the metal On the substrate, the thickness of a single layer of powder is determined according to the characteristics and processing accuracy of different metal powder materials. The specific forming steps are as follows: (1) Put the metal powder on the powder bed and heat up to a suitable temperature; (2) After the step (1) is completed, the laser beam clads and shapes the metal powder according to the two-dimensional plane profile; (3) After the step (2) is finished, carry out the second powder spreading, scrape the surface of the powder bed with a scraper, and then follow the sequence of steps (1) and (2) to carry out a new layer of single-pass cladding molding ; After repeated powder spreading and single-pass cladding molding, the unclad powder and supporting structure can be removed to obtain the metal oral restoration. 4. The method as claimed in claim 1, characterized in that, said step 2 further comprises: when the CAD auxiliary system is in the computer-aided design of the oral restoration, the design of the connection between the metal bracket and the artificial tooth is beneficial to the promotion of metal-ceramic bonding or Baking-plastic bonded retention structures, these bit structures include retention microspheres, retention microspheres, or honeycomb structures that increase the bonding area.