The clinic wants to introduce 3D printing, but it is a little confused about the materials. Are all 3D printing materials in the dental field made of resin?

According to the application types, it can be divided into high-precision dental molds, water-washed dental molds, high-temperature resistant dental molds, special casting wax molds, removable denture bases, implant surgery guidance, temporary crowns and bridges and other materials suitable for different dental 3D printing applications. We have talked a lot about the specific application of each dental 3D printing material. This time, from the post-processing situation of dental 3D printed materials, the classification is as follows: 1, and conventional type: non-washable materials. Nowadays, in the field of stomatology, 3D printing is widely used. The 3D printing materials used in stomatology are mainly 3D printing polymers, among which photosensitive resin has faster curing speed, smoother appearance after molding, low odor and no irritation, which is very suitable for stomatology. For example, there are currently 10 kinds of high-precision 3D printing resins for dentistry, and each material has a corresponding application direction. This series of medical grade 3D printing materials can assist in the production of various dental medical products and meet the digital production needs of most dental laboratories and hospitals. Most dental 3D printing materials are not washable and need post-treatment. Some cleaning materials need solvents such as alcohol and isopropanol. 2. Emerging types: washable materials

In the past, everyone paid attention to what kind of dental products each material could produce, but paid little attention to the cleaning and polishing of these dental 3D printed materials after printing the corresponding dental products. Recently, Haig Technology's UltraPrint series has added a new member-a new water-washed 3D printing material. This material was independently developed by Haig. After the dental model is printed, it can be cleaned directly with sonic cleaner and clean water. The whole process only takes a few minutes. Can be completed. It not only improves the safety and biocompatibility of the product, but also simplifies the process steps of post-treatment. Avoid the unpleasant smell and environmental pollution caused by the use of alcohol and isopropanol in traditional cleaning. The above classification is based on the post-processing and cleaning methods of dental 3D printed materials. In contrast, the new materials of water washing are more environmentally friendly, but not all of them can be made into water washing based on the particularity of dental 3D printing materials. 1. Material type: 1. 1 metal material: Dental medical metal products require metal materials to have good mechanical properties, chemical characteristics, biocompatibility and corrosion resistance. The requirements for raw materials are also very high, with high purity, low oxygen content, fine particle size, good plasticity and good fluidity. At present, the 3D printed metal powder materials mainly used in stomatology are: titanium, titanium alloy, cobalt-chromium alloy, stainless steel and so on. Among them, titanium and titanium alloy materials have the advantages of low density, high precision, high strength and good biocompatibility, and are regarded as ideal metal materials for 3D printing in stomatology. Especially, it is widely used in the fields of oral and maxillofacial repair, tooth tissue repair, implant manufacturing and so on. Due to some performance defects of pure titanium, such as the strength of pure titanium is not as high as that of titanium alloy, and the elastic modulus of pure titanium is higher than that of bone tissue, it is easy to cause mechanical stress incompatibility between titanium implant and bone tissue. In this regard, many researchers try to improve the properties of pure titanium by various methods, such as adding a coating on its surface or oxidizing the surface of pure titanium. 3D printed cobalt-chromium alloy is also a commonly used restorative material in stomatology. It is made by 3D printing technology, and then artificial teeth are added by restoration technology, so that the restoration will have a good fit after entering the mouth. Due to the different materials used in the Co-Cr alloy denture bracket and the added artificial teeth, it is basically impossible to print a complete restoration at one time according to the current technical facilities. Traini et al. formed gradient Ti-6Al-4V titanium alloy porous dental implant with more optimized physical and chemical properties. The tensile strength, area shrinkage and elongation all reach AMs4999 (the related standard of 3D printed titanium alloy issued by American Materials Association). Figliuzzi et al. used laser sintering personalized titanium alloy (Ti-6Al-4V) implant, which was implanted immediately after tooth extraction. Follow-up shows that personalized planting and aesthetic effect are good. Traini et al. laser sintered the titanium alloy specimen, and then measured the elastic modulus of the porous layer on the surface and the dense layer inside the specimen. The former is close to bone cortex and the latter is close to machined titanium metal, which shows that this method can reduce the surface stress and is beneficial to the long-term stability of implants. Mangano et al. used laser sintered narrow-diameter implants for implant restoration of patients' posterior teeth. After two years of follow-up, the survival rate of 37 implants was 100.0%, and the success rate was 94.6%. In terms of physical and mechanical properties, biological corrosion resistance, compatibility, etc., it is necessary to deeply study whether the metal products related to 3D printing are the same as those manufactured by traditional processes and meet the national standards. At present, emerging metal materials are still in the state of in vitro research in the field of stomatology, especially the properties of dental implant materials still have great research space. At present, with the continuous development of 3D printing technology, the continuous optimization of equipment performance and the continuous emergence of various metal printing materials, metal 3D printing technology will be more widely used in various fields of stomatology. 1.2 polymer materials: polymer materials have become a basic and mature printing material in the field of 3D printing. As a representative of polymer materials, plastics have good thermoplasticity, fluidity, rapid cooling adhesion and rapid curing performance. In addition, polymer materials can form new composite materials with ceramics, glass, fiber, inorganic powder, metal powder and so on. In stomatology, polylactic acid, polycaprolactone, hydroxypropyl fumarate, etc. Are common 3D printed materials. Polylactic acid (PLA) is an environmentally friendly material with good biodegradability. It can be completely degraded by microorganisms in nature under certain conditions and eventually produce carbon dioxide and water, which will not cause environmental pollution and is very beneficial to environmental protection. It is recognized as an environmentally friendly material. It is also translucent and shiny, and is an ideal material for 3D printing in stomatology. Polyether ether ketone (PEEK) is a thermoplastic polymer, which is currently used to manufacture 3D printed satellites and 3D printed auto parts, and has begun to exert real influence in the 3D printing industry. The advantages of PEEK material include: ① the elastic modulus of peek material is similar to that of human skeleton, and the stress of the repaired skull is complete; ② Good X-ray performance, no metal artifacts, no influence on medical images, and easy to detect postoperative recovery; ③ The structure made of 3D printed PEKK material has better antibacterial performance than traditional PEEK, and can be sterilized and reused at high temperature; (4) (4) PEEK has strong inertia, little stimulation to scalp, low rejection rate and high stability. Currently used to manufacture denture parts. From the development of 3D printing technology, photo-curing rapid prototyping is the earliest and most mature technology, and it has been widely used. Photosensitive resins for 3D printing, i.e. photocurable resins and UV resins, are polymer materials widely used in stomatology. For the field of stomatology, liquid resin materials need to have excellent stability, low viscosity, rapid curing and high degree. It is found that liquid photosensitive resin can be printed into biodegradable tissue engineering scaffold, and the scaffold made by light-curing rapid prototyping technology has the same mechanical properties as human cancellous bone, and can promote the adhesion and differentiation of fibroblasts. The rapid development of light-cured resin materials constantly promotes the progress of stomatology, which is conducive to the individualization and accuracy of stomatology. 1.3 ceramic materials: ceramic materials in the field of stomatology require good aesthetics and biocompatibility, and have excellent physical and chemical properties such as low density, high strength, high hardness, high temperature resistance, corrosion resistance and good chemical stability, which are widely used in machinery manufacturing, aerospace, biomedicine and other industries. Because of its excellent mechanical and aesthetic properties, it is also used as a dental restoration material. When zirconia ceramics are processed by cutting technology, a lot of materials will be cut off, which will lead to waste, high price of all-ceramic crowns and possible internal cracks caused by cutting force in dentures. The material utilization rate of 3D printed zirconia ceramic denture can reach over 90%, and the cost is relatively low. 3D printing zirconia can reduce material waste and environmental pollution, and bionic mechanical properties such as hardness can be achieved by printing special internal structure. The early 3D printing manufacturing of zirconia was mainly based on laser sintering, but there were some problems such as low density and molding efficiency, rough surface and cracks. Light-cured ceramics have good surface quality and controllable structural accuracy, which has quickly become a research hotspot. At present, there are still some problems in the 3D printing process of zirconia materials, such as large internal stress, easy cracking after sintering and large volume shrinkage, which may affect its mechanical properties and clinical applicability. Ceramic materials and their processing technology still need further study. 1.4 biological tissue materials: It is the pursuit of many scholars to produce human cells, tissues and organs with good biological functions by using 3D printing materials and technologies. Scholars continue to explore 3D printing technology, and closely combine it with biological tissue engineering technology to create artificial cells, tissues and organs with biological functions to replace the human defective tissues that need to be repaired. Hydrogel is a water-soluble polymer, which is produced by chemical or physical crosslinking and is a three-dimensional network structure. Hydrogels have excellent biocompatibility, which can be used to construct tissue engineering scaffolds and can be processed to form drug controlled release carriers. However, at present, the hardness of hydrogels made by 3D drawing biological writing is low, which may lead to structural collapse or limit the complexity of shapes. Therefore, the latest progress of 3D printing biomaterials will promote the progress and development in the field of 3D printing biomaterials. In the field of stomatology, 3D printing products have played an important role in the fields of dentistry and oral surgery, whether customized biological tissue materials or existing finished products. At present, 3D printing technology has basically realized the biological printing of human dental pulp cells (hDPCs), which laid the foundation for the wider application of 3D biological printing technology in tooth tissues. In addition, the fusion of artificial bone material hydroxyapatite and photopolymer can be used to manufacture bioactive bone tissue engineering scaffold. In terms of planting science, 3D printed personalized implants have become the trend of immediate planting. Surface modification of titanium implants can promote the growth and differentiation of osteoblasts, and implants have better characteristics. The micron-scale surface roughness generated by 3D printing technology is more easily recognized by specific cells. Implants with micro-nano composite structure can promote the proliferation and extension of cells, which is more conducive to the differentiation of cells into bone. In the physiological three-dimensional bionic environment provided by micro-nano composite structure, it is more conducive to the extension of cells, thus better proliferation and differentiation.