Stomatology changes due to 3D printing

Written by: Zeng Weiqing In 2016, a 23-year-old student majoring in design at New Jersey Institute of Technology made headlines on major news websites around the world for an unprecedented “feat”. He used the school to provide students with freedom without the intervention of a dentist. Using the laser scanner and 3D Printing equipment, we have produced 12 sets of transparent braces suitable for ourselves and successfully corrected the original defective teeth. The whole process is divided into “sodium alginate powder moulding-scanning to obtain 3D digital models-3D Print orthodontic model—vacuum injection molded transparent braces”. However, this is not an isolated case. Similar mass incidents are being staged vigorously in the United States. According to Xu Sheng, an associate professor at the Guangxi Medical University School of Stomatology, there is a dental beauty startup called “SmileDirect Club” in the United States that can assist patients without the assistance of a dentist. Take the model by yourself, and then send it to the processing factory, use the above method to make invisible braces for the patient, and be responsible for the post-maintenance. The whole process completely surpasses the professional design and inspection of traditional dentists, and reduces the cost of orthopedics and orthodontics to Unbelievable degree. Regardless of whether this move is worthy of emulation and promotion, what is behind the incident is that 3D Printing will bring varying degrees of change to dentistry and even the entire dentistry. This view is also recognized by Associate Professor Xu Sheng, a senior dentistry expert and materials scientist: “The next ten years will be 3D printing that will promote major changes in dentistry technology. The treatment methods, processes and medical models will be changed due to 3D printing. .”

The specific application of 3D printing in dentistry In the 1990s, Associate Professor Xu Sheng completed the Bachelor of Stomatology and Master of Materials at the School of Stomatology of West China Dental University (Sichuan University), and then worked in West China Dental Implant Hospital for nearly ten years. , Currently works in the Stomatological Hospital of Guangxi Medical University, during which he went to Germany, Japan, and the United States for research and study. These professional studies and clinical skills made Xu Sheng feel that the backwardness of traditional technicians’ manual craftsmanship and material technology has deeply restricted the development of dental clinical applications, and new technologies and materials are needed to promote the progress of dental medicine. “We have a sentence It is called “The development of dentistry does not depend on the dentist itself, but on the development and progress of other fields of technology.” Xu Sheng said, and 3D printing is just such an advanced manufacturing technology, which combines 3D scanning and computer software algorithms. Technology, can well replace artificial, it is not only used in a large number of personalized dentures, it will also play a huge role in invisible correction, surgical guides, maxillofacial restoration and other fields. “In fact, more and more clinics, hospitals, and departments are beginning to pay attention to the application of 3D printing and CAD/CAM technology. The Stomatological Hospital of Guangxi Medical University has also spent tens of millions of funds to purchase 3D printing equipment.” Xu Sheng revealed. It is understood that currently the 3D printing equipment purchased by the Dental Hospital of Guangxi Medical University are mainly imported plastic and resin printing materials, and the “Regenove” biological 3D printing equipment of Hangzhou Genovei has also been purchased for the next step in the study of biological 3D. The printing technology laid the foundation, and in the metal 3D printing technology, it mainly cooperated with external manufacturers, and established with Guangdong Zhiwei Three-dimensional Molding Technology Co., Ltd. (hereinafter referred to as “Guangdong Zhiwei”), an excellent domestic manufacturer of 3D printing equipment Very good exchange and cooperation relationship, the two sides have burst out a lot of thoughts in 3D printing technology and oral clinical application. At present, what are the applications of 3D printing in dentistry? Associate Professor Xu Sheng gave us a detailed introduction based on the classification of stomatology: First of all, the best and most impressive dental field where 3D printing is currently used is orthodontics. 3D printing has largely penetrated into the production process of invisible braces and personalized lingual orthodontic appliances.

Take invisible braces as an example. In the traditional orthodontic treatment process, after the doctor obtains the patient’s dental model, he manually saw off the teeth that need to be moved one by one, arranges the teeth to a movable position, and heats them. Compression molding technology directly extrudes the transparent braces to be worn by the patient. The distance of movement may be only 0.1 mm, which not only requires a lot of time and energy, but also requires the professional knowledge and manual craftsmanship of the operator to be very high, and it is cumbersome. Plaster molds are not convenient for storage, transportation, and communication between doctors and patients. 3D printing replaces the manual arranging of dental molds. You only need to pre-arrange the digital dental molds to the ideal position through professional software on the computer. According to the orthodontic theory and big data results, use extremely high-precision dental molds. Resin 3D printing resin dental molds in different stages can be used to press out transparent braces with the previous laminating process, and its accuracy and speed are naturally self-evident. In lingual correction, 3D printing can be used to make personalized brackets, but the cost of this method is still relatively high. At present, most hospitals take a middle route. First, 3D print the brackets with plastic or wax. Shape, and then use traditional casting methods to manufacture lingual orthodontic components. Secondly, the field of prosthodontics that usually receives the most attention is the field of prosthodontics, the essence of which is to inlay a new tooth for the patient’s missing or missing tooth. Xu Sheng believes that this is the earliest application field of 3D printing, because 3D printing can directly tailor a metal or ceramic tooth for the patient. After polishing, the veneer porcelain can be put on the patient’s mouth. At present, the Dental Hospital of Guangxi Medical University adopts two 3D printing modes. One is to print out the plastic shell, which is embedded, cast and polished to make the crown, and the other is to use laser metal melting directly. Way to print out metal dentures or ceramic teeth. Third, 3D printing has also been practically applied in the field of orthognathic surgery. Patients with maxillofacial fractures and bone defects due to maxillofacial trauma, tumors, etc., need to restore the normal shape of the maxillofacial area. Doctors can use CBCT. Reconstruction of the three-dimensional maxillofacial anatomy and 3D printing of the skull model can intuitively guide the doctor to plan and simulate surgery. Moreover, it is possible to directly 3D print out the defective parts of the patient’s maxillofacial region, such as a metal titanium mandibular scaffold, which can be implanted into the patient’s mandible, allowing the patient to return to a normal appearance and perform appropriate functions. Furthermore, the team of Dean Zhou Nuo of Guangxi Medical University Stomatological Hospital is researching bio-3D printing, experimental research on 3D printing bone tissue and other tissues for the treatment and restoration of maxillofacial defects and deformities in clinical applications. In addition, in oral implants, 3D printing is currently mainly used for the production of implant guides. Because in dental implant surgery, it is necessary to use implant software to first analyze the bone mass in the implant area, distinguish and measure important anatomical features such as the maxillary sinus and inferior alveolar canal, and then design the size, optimal position and orientation of the implant . The 3D printed guide plate can accurately guide the doctor to implant the implant to the most suitable position, that is, it will not cause damage to important tissues, and it can achieve the purpose of restoring the function of the implant. According to Associate Professor Xu Sheng, 3D printed guides will no longer be needed in dental implants in the future. At present, Guangxi Medical University Dental Hospital is using VR simulation to train students to use implant handles with sensors, and implant handles with sensors and VR Realistic technology is applied to actual clinical surgery, and it simulates and guides the doctor to complete the precise implantation operation without the guide plate.

The cost of 3D printing restricts the promotion of applications. It is undeniable that technological progress has given us unlimited reveries, but even in the most promising application field of 3D printing-stomatology, there are still many applications and promotion. According to Xu Sheng’s introduction, “At present, the CAD/CAM technology of subtractive manufacturing that is actually used in the field of denture processing accounts for 20% and higher proportions. 3D printing is not widely used in clinics, although 3D printing projects are increasing, and everyone is willing to adopt this technology, but there are still some bottlenecks.” Among them, the biggest promotion bottleneck in denture processing and braces production is the high cost of 3D printing, and it is more systematic. In the application research of 3D printing, the technological maturity of 3D printing needs to be improved. At present, only relatively simple and single projects can be done. 3D printing still needs more technical research and thinking. Judging from the two cases we mentioned at the beginning of the article, students from the New Jersey Institute of Technology in the United States designed and produced 12 transparent braces by themselves. The entire material cost was only 60 US dollars (less than 400 yuan). In 2014, the American “SmileDirect Club” dental beauty startup also reduced the hospital’s original tens of thousands of dollars in fees to an incredible level. It sounds like 3D printing has brought very optimistic cost benefits. But what we need to know is that at present, the vast majority of people in China cannot spare the doctor’s expertise and time cost to design their own braces. In the United States, dentists have sued the “Smell Direct Club” company to court. Such a lawsuit is still pending and there is no way to judge. Therefore, from the perspective of Xu Sheng as a doctor, the cost of 3D printing is still too high. Take the steel support of removable dentures as an example: using the casting method, the total cost is 40 yuan. ; Reduced material cutting is about 150 yuan, which includes the wear of the cutter head, but a lot of material waste; and the 3D printing technology method using laser melting, the cost is nearly 300 to 400 yuan, which does not include equipment depreciation, laser head The cost of depreciation. Considering the cost issue, even if 3D printing is good, doctors are more willing to recommend the use of 3D printing technology to produce high value-added pure titanium steel support for reasons of cost performance. In the field of transparent invisible braces that are currently the most widely used in 3D printing, taking 30 pairs of braces for a patient as an example, the clinical price of 3D printing is about 40,000 to 50,000 yuan and higher, while the cost of correction using traditional orthodontic solutions About 20,000 yuan (varies depending on the medical unit). According to Xu Sheng’s analysis, currently in China, the main force for orthodontics is young people who are in school or who have just worked or graduated. The spending power of most of them Can not reach such a high level, therefore, the current cost can be said to greatly limit the large-scale adoption of this technology. The maturity of 3D printing technology itself, the choice of materials, the diversification of colors, and the stability of performance have not yet reached the research needs of doctors for complex projects. Xu Sheng introduced that he is currently doing a more personalized research project, which is to use 3D printing technology to make personalized ceramic teeth with aesthetic characteristics. Different parts of the dentures are required to have different strength functions and color changes. Trying to use different porcelain powders to print different parts of the teeth, so that the ceramic teeth show 3D tooth color changes and transitions of different characteristics, and then sinter after printing to achieve the required strength and color matching of the teeth. But according to As far as I know, 3D printing for dentistry can’t provide such personalized printing. This is the problem we are facing.” Associate Professor Xu Sheng is also working with various manufacturers, hoping to develop such a technology to solve dentists. Higher aesthetic requirements.

The future changes that 3D printing will bring to dentistry. In the future, with the reduction of the cost of 3D printing and the optimization of the process flow, Xu Sheng believes that the general trend in the next five to ten years is that “3D printing will definitely change the treatment and treatment methods of dentistry. Production methods and even related theories of stomatology may change accordingly.” Especially in the dental field, in June 2017, Transparency Market Research, a well-known market research institution in the United States, released a research report predicting that the global dental 3D printing market will exceed US$3.4 billion by 2025. Xu Sheng also predicts that several development trends in the dental field are foreseeable: 1. The proportion of 3D printing in denture manufacturing will increase step by step, and the traditional denture production model will be more impacted; 2. Dental clinics will be more and more affected. Favor 3D printing and CAD/CAM. If the production cost and talent training can closely meet the needs of the clinic, the dental clinic will have its own denture manufacturing equipment and dental workshop, and can make most of the required dentures by itself; 3. 3D printing will likely change the development model and direction of dental clinics. The traditional one-by-one clinics may form a community-style chain clinic, while the digital processing center for dentures will exist in a model similar to a central kitchen. After the data sent by the doctor, the personalized and customized dentures for clinical needs can be manufactured quickly, and delivered to the dentist by express delivery. The new service concept of one time model will be greatly promoted and applied. 4. As mentioned earlier, 3D printing may have a greater impact on orthodontists. With the development of computing and artificial machine intelligence technology, AI is likely to exceed the knowledge of dentists in terms of professionalism. The limit that can be reached, then the traditional dental treatment process will have to be changed. If 3D printing is a technology that can change people’s food, clothing, shelter, and livelihood, then this change will undoubtedly start from changing a small tooth in our mouth. Dental medicine, especially dentistry, as the most promising field of 3D printing applications, will bring huge changes because of it, not only dentists are looking forward to it, but the general public is also waiting to see.