WO2018014636A1

WO2018014636A1 - Cad/cam/slm-3d combined printing method for dental restorations

Info

Publication number: WO2018014636A1
Application number: PCT/CN2017/084053
Authority: WO
Inventors: 高勃; 刘一帆
Original assignee: 中国人民解放军第四军医大学
Priority date: 2016-07-20
Filing date: 2017-05-12
Publication date: 2018-01-25
Also published as: CN106264762B; CN106264762A

Abstract

Disclosed is a CAD/CAM/SLM-3D combined printing method for dental restorations. A CAD/CAM/SLM-3D combined printing system, constituted by an optical scanning measurement instrument or a contact scanning measurement instrument, computer-aided design software for dental restorations, a miniaturized metal 3D printer, and a numerically controlled milling machine, is used to prepare a metal restoration, combining the existing dental CAD/CAM system with a metal 3D printing technique to combine the respective numerically controlled processing methods thereof so as to maximize the effects. The method can improve the automatic production efficiency of metal dental restorations, especially complex metal dental restorations, and eliminate the cumbersome procedures in the traditional manual manufacture for dental restorations. Thus the method improves the manufacturing quality and stability of restorations, achieving the purpose of rapid, accurate and personalized manufacturing, and better satisfying the urgent requirements of patients with tooth loss.

Description

Dental prosthesis CAD/CAM/SLM-3D printing composite method

Technical field

The invention relates to an automatic processing method for a dental prosthesis, in particular to a dental prosthesis CAD/CAM/SLM-3D printing composite method, which combines the existing dental CAD/CAM system with metal 3D printing technology and exerts its own Long, the combination of their respective CNC machining methods, the effect to the extreme, to achieve the goal of making dental prostheses quickly, accurately and individually.

Background technique

Computer aided design (CAD) and Computeraidedmanufacture (CAM) technology combines the knowledge and technology of mathematics, optics, electronics, computer image recognition and processing, automatic control and automated processing. It was widely used in industrial automation and aerospace in the 1970s. In 1983, the first dental CAD/CAM system prototype developed by Duret of France was introduced in France. At the International Dental Conference held in France in 1985, Professor Duret used the equipment to make the first crown of the back porcelain and successfully used it. In the patient's mouth, making CAD/CAM a reality in the field of stomatology. 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 are available. At present, more than 10 kinds of CAD/CAM systems have been introduced, which can be used to make inlays, veneers, full crowns, partial crowns, fixed bridges, implant bridges, etc. However, the removable partial denture and the complete denture are still in the research stage, and there is no mature system. The oral CAD/CAM system usually consists of three parts: data acquisition (digital impression), computer aided design (CAD), and computer aided production (CAM). An emerging dental prosthetic technology has begun to take shape, and the CAD/CAM system has made oral prosthetics a modern high-tech field.

1. The main CAD/CAM system

Among the current commercial dental CAD/CAM systems, CNC milling machines are an important component. The prosthesis is machined using a CNC milling method that uses a cutting tool to remove excess material to obtain a restoration that meets the shape, size, and surface roughness requirements. This technology is essentially a category of material removal, namely "subtraction."

1.1 Cerec system:

The Cerec system was developed by the German Ministry of Dental Engineering (SIEMENS), now the German SIRONA Dental Equipment Co., Ltd. Its product line includes CerecI, CerecII and CerecIII as well as CerecinLab. Among them: CerecIII was born in 2000, Cerec III system is based on Windows platform, the cutting system and image acquisition system work independently, and the software system has been greatly improved, which makes the Cerec III system can make inlays, onlays, veneers and parts. Crown and full crown. However, the Cerec III software system can only be designed on the plane, and it is difficult to display the overall shape of the restoration. The Cerec3D system was first exhibited at the Hinman Dental Congress in Atlanta, USA in March 2003. It introduces a multi-dimensional perspective when designing the restoration, allowing you to visually examine the shape of the restoration and the abutment from a 3D perspective. Cerec3D software system has added 3D design software such as FrameWork to realize the repair of all-ceramic fixed bridge. In 2002, Sirona introduced the Cerec inLab system, which was specially designed for the lab. It uses a laser scanning system to collect dental data. The restoration is made faster, has a wider range of applications, and can be used with higher intensity. Alumina, zirconia ceramic materials.

1.2 Celay System:

The Celay system was designed by the Zurich School of Dentistry and first exhibited in Munich in 1990 and is now produced by the Swiss company Mikroma. The system is not a CAD/CAM system in a complete sense. The principle is similar to a small key copying machine. It consists of two parts, a contact sensor and a micro-milling machine. The sensor head is “read” in the mouth or on the model. Hard surface wax or resin restoration surface shape data, and the data is simultaneously transmitted to the milling machine to simultaneously process the porcelain restoration. The system is simple in composition and low in automation. When working, you must first make a temporary restoration in the mouth or on the model as a source of information for obtaining data. The Celay system mainly uses aluminum oxide machinable ceramics to process inlays or onlays with occlusal surface morphology, as well as base crowns for full crowns or fixed bridges.

1.3 Procera system:

The Procera system is a Swedish system and was introduced to the market in 1993 by Nobel Biocare. Now, the system uses Procera Piccolo or a more advanced ProceraForte scanner to collect data on the dental model. The physician designs the prosthesis through ProceraLofrwore 2.0 software, and after the design is completed, the data is transmitted to the four production centers designated by the Procera system via the Internet ( Stockholm, Sweden; FairLawn, NJ, USA; Karlskoga, Sweden; Tokyo, Japan). The processing center can be directly processed into the final zirconia and alumina all-ceramic crown bridge according to the doctor's requirements, or it can be processed into zirconia and alumina substrates to be post-posted and then surface-mounted porcelain. In addition to being used to make natural tooth crowns, the Procera system can also be used in the field of planting. The Procera system can cut a single tooth abutment of pure titanium or zirconia, which can be used to personalize the height, angle and edge shape of the abutment; the Procera system can also cut a plant made of pure titanium or zirconia. It can provide up to 14 units of plantation bridges with excellent biocompatibility, excellent strength and aesthetics.

1.4 Cercon system:

The Cercon system scans the data on the dental model through the CerconEyeScanner 3D laser and transmits it to the CerconArtCAD section to design the restoration. The transmitted information is then passed to the CerconBrain section to cut the restoration or pass the information over the Internet to York. The production center processes the restoration. Therefore, for some small dental clinics or technician centers, you can purchase only the CerconArt CAD part of the Cercon system (which already includes the CerconEyeScanner scanner), thus reducing costs. CerconArtCAD provides a fine design for the edges of the prosthesis and the occlusal surface. The Cercon system is based on zirconia structural ceramics and can be used to make post cores, implant abutments, full crowns and fixed bridges.

1.5 Lava system:

Lava system was launched by American 3M Company in 2002 and consists of Lava Scan, LavaCAD, LavaForm, LavaTherm and so on. Firstly, the non-contact 3D optical scanning system was used to collect the data on the dental model. The physician used LavaDesign4.0 software to design the prosthesis. Cutting the pre-sintered zirconia block to obtain the base crown requires an average of 35 minutes per unit crown. After the cutting is completed, the crown base crown is completely sintered, and then the surface porcelain is added on the surface. Compared to the Vita colorimetric system, the Lava zirconia base crown has 7 color choices, and the veneer porcelain has 16 color choices. Therefore, the restoration made by the Lava system has the closest color and light transmission to natural teeth. It is suitable for the repair of fixed bridges with 3~4 units for single crown and front and back 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: Everestscan, Everestengine, Everesttherm, and Everestelements. First, the Everestscan data scanning system (using a CCD camera) collects the data on the dental model. The operator uses the ENERGYCAD software to design the prosthesis in three dimensions, and then the CAM part is cut on the X, Y, Z, A, and B axes. Prosthesis. Therefore, the restoration made by the Everest system has good processing precision and clear anatomy. The Everest system can process a wide range of materials, including zirconia, alumina, pure titanium, glass ceramics, gold, resins, etc., for 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 and assembled by different companies. There are two options for the more mature open systems on the market today:

1) 3Shape dental scanner + CAD software + German CNC lathe, which can process all brands of zirconia, plastic, not subject to brand restrictions;

2) 3Shape dental special scanner + CAD software + American 3Dsystem wax type machine, after casting wax type, you can embed casting metal or make all-ceramic crown. Compared with other CAD/CAM systems, open systems have the advantage of being able to process a wider range of materials and at a lower cost.

2. CAD/CAM system for additive manufacturing

The above-mentioned CNC lathe cannot cut a restoration with a complicated structure (such as a hollow structure) and cut The waste of materials during the cutting process has become a key issue in the advanced manufacturing technology of oral restoration. Rapid prototyping technology, referred to as RP or RPM technology (RapidPrototyping/RapidPrototypingManufacturing), is an advanced manufacturing technology developed in the late 1980s. The technology combines computer-aided design (CAD), computer-aided manufacturing (CAM), computer numerical control (CNC), precision servo drive, laser and materials science into one, adopting the idea of discrete-stack stacking, basic idea Yes: Any 3D part can be thought of as the superposition of many 2D planar contours along a certain coordinate. However, RP technology cannot directly produce metal restorations to meet the needs of oral restoration. In the late 1990s, the Rapid Manufacturing Technology (RM), which was established by the combination of RP technology and laser coating technology, used a laser to deposit the powder material layer by layer by means of pre-laying or simultaneous powder feeding. Components. The formed parts have excellent physical and chemical properties and are not limited by complicated structures. RP technology and RM technology are essentially additive production, that is, "addition".

Gao Bo, the Fourth Military Medical University of the Chinese People's Liberation Army, applied for the Chinese patent for "Laser Stereo Forming Method for Oral Metal Prostheses" in 2003 and was authorized in 2005 (Patent No.: ZL03134316.3). At present, the mainstream of 3D printing of metal restorations is SLM (selective laser melting) and EBM (Electron Beam Melting). The former mainly produces cobalt-chromium alloy crown bridges, crown bridge bases or removable partial denture brackets. The latter is mainly used for metal implants. Body production.

2.1 Application in fixed repair:

In 2004, Bennett used the MCPRealizer device based on SLM technology to make base crowns, fixed crowns and fixed bridges of cobalt-chromium alloy and stainless steel. The crown shape was good after fabrication. In 2005, the French scholar Nadine applied the PhenixSLM system developed by himself to design and manufacture the base crown of nickel-chromium alloy. The shape and precision of the base crown were good. After the hand-clad porcelain, the porcelain crown was very good. Color matching and edge suitability.

2.2 Application in removable partial dentures:

In 2006, Williams and others made CAD/CAM technology on the SLMRealizer2 machine. Cobalt-chromium alloy stent with removable partial denture. Domestic Wu Lin and others initially realized the computer-aided design of the Kennedy Class II dentition defect model, and processed the resin mold of the removable partial denture bracket with a laser rapid prototyping machine. In 2009, Zhu Senyang and other computer-aided design and production of Ken's Class I dentition defect removable partial denture stent.

2.3 Application in full dentures:

The complete denture has a complex shape and various materials for the denture. The current full denture CAD/CAM research is relatively lagging. Gao Bo, the Fourth Military Medical University of the Chinese People's Liberation Army, designed the maxillary half-metal base denture through the Surfacer software, and used the laser stereo forming technology to initially 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 series of laser rapid prototyping complete dentures of pure titanium substrates: LasersMedSci (2010) 25:309–315; RapidPrototypingJournalVolume15, Number2, 2009, 133–136 And the suitability of its research, clinical test results show that its production accuracy needs to be improved.

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

The application of CAD/CAM technology in the oral field has greatly improved the repair efficiency, shortened the patient's treatment cycle, reduced the patient's pain and reduced the labor intensity of the technician, and made the dental prosthesis revolutionized. However, there are still the following problems in the clinical application process: the current CAD/CAM system is mainly used in the field of fixed repair, but the main reason for the lack of application in removable partial dentures and full dentures is the inherent limitations of CAD/CAM system cutting. Sexuality not only causes waste of materials, but also makes the type of restoration produced so that it cannot cut the composite of the composite.

In summary, if the traditional CAD/CAM system's cutting manufacturing technology can be combined with the currently mature metal 3D printing technology, it is the future direction of dental prosthesis.

Summary of the invention

In view of the above-mentioned defects or deficiencies of the prior art, the present invention aims to provide a new dental composite CAD/CAM/SLM-3D printing composite method, which will be used in the existing oral CAD/CAM system. Combined with metal 3D printing technology, organically process each CNC machining method Combine, develop their respective strengths, and maximize their respective advantages to produce oral metal restorations quickly, accurately and individually.

In order to achieve the above tasks, the present invention adopts the following technical solutions:

A dental prosthesis CAD/CAM/SLM-3D printing composite method, which is characterized in that the method adopts an optical scanning measuring instrument or a contact scanning measuring instrument, a computer aided design software for a dental prosthesis, a miniaturized metal 3D printer and A dental prosthesis is prepared by a CAD/CAM/SLM-3D printing composite system composed of a numerically controlled milling machine. The dental prosthesis is a composite restoration composed of a material, the base or the bracket portion thereof is a metal, and the ceramic surface is ceramic. Or plastic; from the type of restoration is a porcelain or roasting crown bridge, or removable partial denture; specifically as follows:

1) routinely complete the three-dimensional shape scan of the patient's intraoral or extraoral plaster model and establish a digital model consistent with the oral missing condition, referred to as the A model;

2) Using computer-aided design software to complete the metal substrate or branch architecture design of the dental prosthesis on the A model, referred to as the B configuration, the data format is 3D printer compatible STL format;

3) Aligning the B configuration in the computer-aided design software to the original position of the A model, and on the basis of this, complete the matching artificial tooth configuration design corresponding to the metal substrate or the bracket, referred to as the C configuration;

4) Input the B configuration data into the 3D printer, select the metal powder material that meets the national medical material license, and use the 3D printing process of the selective laser melting technology (SLM) to make the corresponding metal bracket, referred to as the D structure;

At the same time, the C structure data is input into the CNC cutting machine tool, and the dental ceramic or plastic blank obtained by the national medical certification is selected, and the artificial tooth data configuration matching the upper part of the B configuration is cut out, which is referred to as the E configuration;

5) The D structure and the E configuration are assembled and bonded to obtain a final dental restoration for the patient to wear.

According to the invention, the metal substrate or stent is a removable partial denture for removable partial dentures Metal bracket; for ceramic or baked crown bridges, the metal base of the porcelain or baked crown bridge.

The above CAD/CAM/SLM-3D printing composite system can be placed on a mobile vehicle such as a vehicle or a ship, which is equivalent to a mobile denture digital processing factory.

The new method of the dental prosthesis CAD/CAM/SLM-3D printing composite method of the invention has the advantages of integrated design and synchronous processing. The metal substrate or the support structure type (such as the removable partial denture bracket) and its corresponding upper part match the artificial tooth configuration, and the design is completed before and after the same time. The dental prosthesis is processed by CNC cutting (subtracted material manufacturing, called subtraction). Combined with 3D printing technology (additive manufacturing, called addition), it is highly uniform and synchronized. Raise the two aspects of the unity of contradictions and opposites to the realm of unity. It will greatly improve the automatic production efficiency of dental metal restorations, especially complex dental prostheses, get rid of the cumbersome process of traditional hand-made dental prostheses, improve the quality and stability of dental prosthesis production, and achieve fast, precise and personalized production purposes. To better meet the urgent needs of the majority of patients with missing teeth.

DRAWINGS

1 is a schematic view showing a new method of CAD/CAM/SLM-3D printing composite of the dental prosthesis of the present invention;

Figure 2 is a photograph of a patient's oral missing tooth;

Figure 3 is a photograph of a plaster model obtained by preparing a dental impression;

Figure 4 CAD design drawing of the TC4 alloy bracket for removable partial dentures;

Figure 5 is a realignment of the TC4 alloy stent to its original position on the digitized model;

Figure 6 is a computer aided design of the artificial tooth on the TC4 alloy bracket;

Figure 7 is a 3D printed TC4 alloy bracket;

Figure 8 is a zirconia ceramic triple crown completed by CNC cutting;

Figure 9 is a photograph of a TC4 alloy stent and a zirconia ceramic triple crown assembly.

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

detailed description

In the following embodiments, the applicant employs an optical scanning measuring instrument or a contact scanning measuring instrument, CAD/CAM/SLM-3D printing composite system consisting of computer-aided design software for dental prosthesis, miniaturized metal 3D printer and CNC milling machine. The system consists of three parts, the first is optical scanning measuring instrument or contact scanning measurement. The instrument completes the digital collection of the oral cavity by scanning the plaster model, the impression made in the mouth, and directly scanning the soft and hard tissues in the mouth; the second is the computer-aided design software of the dental restoration, and the computer for completing the configuration of the dental restoration Aided design. The third is a miniaturized metal 3D printer and a CNC milling machine. The 3D printer prints the designed metal substrate or bracket CAD data with metal powder, and the metal powder meets the national medical license standard. CNC cutting ceramics or plastics also need to comply with national medical licensing standards.

The dental prosthesis is composed of a composite material restoration, the base or the bracket part is metal, and the metal surface is ceramic or plastic; the repair type is porcelain or roasting crown bridge, or pickable Partial denture.

Finally, the plastic or ceramic artificial tooth is assembled and bonded on the metal substrate or the bracket, thus completing the rapid preparation of the dental restoration.

The specific production method is shown in Figure 1:

1. Regularly complete the three-dimensional shape scan of the patient's oral or extraoral plaster model and establish a data model consistent with the oral missing condition, referred to as the A model;

2. Computer-aided design software is used to complete the design of the metal substrate or bracket (such as the metal bracket of the removable partial denture), which is referred to as the B configuration, and the data format is a 3D printer compatible STL format.

3. The designed B configuration is placed in the computer-aided design software and placed on the original position on the digital model. On this basis, the artificial tooth configuration design matching the upper part of the metal bracket is completed, which is referred to as C configuration;

4. Input the B configuration data into the SLM metal 3D printing, and select the metal powder material that meets the national medical material license.

5. The 3D printer discretizes the 3D data model of the B configuration into 2D planar data, and uses the selective laser melting technique (SLM) to perform 2D planar contour data processing in a preset order. Accumulating, cladding metal powder material to form a metal stent. The specific process is: in the vacuum inert gas processing chamber, the metal powder material is laid on the metal substrate, and the thickness of the single layer is determined according to the characteristics and processing precision of the different metal powder materials, and the specific steps are as follows:

(1) placing the metal powder on the powder bed and heating to a suitable temperature;

(2) After the end of step (1), the laser beam is formed by cladding the metal powder according to a two-dimensional plane profile. (3) After the end of step (2), carry out the second layering, scrape the surface of the powder bed with a scraper, and then re-form the single layer of the new layer according to the steps (1) and (2). After repeatedly laminating, after single-pass cladding molding, the un-clad powder and the support structure are removed, and the metal substrate or the support D can be obtained.

6. At the same time, input the C configuration data into the CNC cutting machine tool, select the oral ceramic or plastic blank obtained by the national certification, and cut out the configuration matching the upper structure of the metal bracket D, such as artificial teeth or artificial teeth, referred to as E structure.

7. The metal substrate or the bracket D and E structures are assembled and bonded to obtain a final restoration for the patient to wear.

In the art, the preparation of the porcelain crown bridge is relatively simple. This embodiment only gives the whole process of making the most complicated removable partial denture in the dental prosthesis. The following is a detailed research process:

1. Materials and equipment

1.1 SLM required materials and equipment

Selective laser cladding machine (EOSINTM280, EOS, Germany). TC4 powder, spherical powder, particle size 15-53 microns (Carpenter, USA). Optical scanning and computer aided design systems (DWOS, DentalWings, Canada).

1.2 CAD/CAM cutting equipment and materials

CAD/CAM system (Ultrasonic20linear, DMG, Germany), machinable zirconia block (Ertron, China).

1.3 Other materials and equipment

Conte "Water Cube" silicone rubber impression material (Conte Dental Group, Switzerland), super hard plaster (Hubei Benoy Dental Materials Co., Ltd.).

1.4 Case selection and design

Referring to Figure 2, a male patient, Jing, 56 years old, with left maxillary premolars and first molars missing, was unable to perform dental implant system and fixed denture repair, and voluntarily performed traditional removable partial dentures.

The removable partial denture is designed as a dental support type, with 13, 17, 23, 27 as the abutment, the lip-cheek side of the TC4 alloy stent is designed as a snap ring, and the wide rear mast is a large joint. A three-crown preparation for connecting artificial teeth (artificial teeth) is designed on the TC4 alloy bracket.

1.5 Computer-aided design of removable partial denture bracket and corresponding crown bridge

The patient was given two oral plaster models (Fig. 3). The first payment model used traditional lost wax casting technology to make a Vitalin metal stent. The dental filling plastic was worn for the patient after it was finished. Another model used a 3shape scanner to obtain a digital model of the plaster model. The design of the TC4 alloy bracket was completed using 3shape's design software (Fig. 4), and the CAD configuration was saved as STL format data1.

Realign the TC4 alloy bracket designed in STL format data 1 to its original position on the digitized model (Fig. 5), and then complete the corresponding three on the TC4 alloy bracket in 3shape's computer-aided design software. The artificial crown CAD configuration design (Fig. 6) of the continuous crown preparation body and the three-joint preparation body is saved, and the obtained STL format data of the artificial tooth CAD configuration is saved.

1.63 D printing TC4 alloy bracket and CNC machining zirconia triple crown

The STL format data 1 was printed on a 3D printer using a selective laser melting technique (SLM) to produce a TC4 alloy holder (Fig. 7). The printing parameters are 400W fiber laser, the thickness of the single layer is 60 microns, and the scanning path is linear filling + outer contour scanning.

At the same time, the STL format data 2 of the artificial tooth CAD configuration is input into the dental numerical control milling machine, and the zirconia artificial tooth triple crown is produced by cutting (Fig. 8).

1.7 TC4 alloy bracket and zirconia triple crown assembly bonding

The zirconia artificial tooth triple crown is assembled to the three-joint preparation of the TC4 alloy bracket (Fig. 9), After being fully seated, it is bonded with an adhesive to complete the final removable partial denture.

Claims

A dental prosthesis CAD/CAM/SLM-3D printing composite method, which is characterized in that the method adopts an optical scanning measuring instrument or a contact scanning measuring instrument, a computer aided design software for a dental prosthesis, a miniaturized metal 3D printer and The dental prosthesis is prepared by a CAD/CAM/SLM-3D printing composite system composed of a numerically controlled milling machine; the dental prosthesis is composed of a composite material restoration, the base or the bracket part is metal, and the ceramic surface is ceramic. Or plastic; from the type of restoration is a porcelain or roasting crown bridge, or removable partial denture; specifically as follows:

1) routinely complete the three-dimensional shape scan of the patient's intraoral or extraoral plaster model and establish a digital model consistent with the oral missing condition, referred to as the A model;

2) Using computer-aided design software to complete the metal substrate or branch architecture design of the dental prosthesis on the A model, referred to as the B configuration, the data format is 3D printer compatible STL format;

3) Aligning the B configuration in the computer-aided design software to the original position of the A model, and on the basis of this, complete the matching artificial tooth configuration design corresponding to the metal substrate or the bracket, referred to as the C structure;

4) Input the B configuration data into the 3D printer, select the metal powder material that meets the national medical material license, and use the 3D printing process of the selective laser melting technology (SLM) to make the corresponding metal substrate or bracket, referred to as the D structure;

At the same time, the C structure data is input into the CNC cutting machine tool, and the dental ceramic or plastic material obtained by the national medical certification is selected, and the artificial tooth matching the upper part of the B configuration is cut out, which is referred to as the E configuration;

5) The D structure and the E configuration are assembled and bonded to obtain a final dental restoration for the patient to wear.
The method of claim 1 wherein said metal substrate or stent is a metal stent of a removable partial denture for a removable partial denture; and a metal for the crown bridge for a porcelain or baked crown bridge Substrate.
The method of claim 1 wherein said CAD/CAM/SLM-3D is played The printed composite system can be placed on a mobile vehicle such as a vehicle or a ship, equivalent to a mobile denture digital processing plant.