As one of the organs of the human body, the oral cavity as a whole and the internal teeth are different from everyone. Therefore, the individual characteristics of dentistry are the most prominent: the dental field requires high precision, and each model design is individualized and will not be repeated. Therefore, before the emergence of 3D printing technology, it was difficult and inefficient to rely on skilled workers to operate manually. Moreover, dental models are generally small. These features make the dental and light-curing 3D printing technology a perfect combination.
The personalized design and high molding accuracy of light-curing 3D printing fully meet the needs of the field of dental medicine. At present, light-curing 3D printing technology is used in the production of dental correction aids such as invisible orthodontics, fixed teeth, implant surgery guides, removable denture bases, and personalized restoration investment molds, as well as dental implants, restorations, and orthodontics. The fields of orthodontics and internal medicine have developed rapidly. Thanks to light-curing 3D printing, the development of dental medicine has increasingly met the needs of the general public for personalized treatment, and the two complement each other.
With the emergence and maturity of 3D printing technology, and its perfect integration with the dental field, it promotes the emergence of a new technology-dental digital technology. Dental digitization refers to the aid of computer technology and digital equipment to assist in diagnosis, design, and treatment. This technology not only simplifies the cumbersome manual work procedures, but also overcomes the bottleneck of low manual accuracy and low efficiency. Through 3D scanning and CAD/CAM design, the dental laboratory can accurately, quickly and efficiently design auxiliary treatment tools such as invisible orthodontics, fixed teeth, implant surgical guides, and directly produce resin models from the designed data through 3D printing technology. Realize the digitization of the whole process. In short, the application of 3D printing technology further simplifies the manufacturing process and greatly shortens the period of oral restoration.
3.1 Application of light-curing 3D printing in the field of dental orthodontics
The traditional orthodontic model is to obtain a silicone rubber impression of the patient's upper and lower jaws, and then infuse plaster to form a plaster model. Orthodontic models can fully display the relationship between the patient's teeth, dentition, and basal bones. In the process of orthodontic treatment, such as tooth arrangement, accurate bonding of orthodontic brackets, occlusal balance treatment, and invisible braces without brackets The production and other aspects play an indispensable role, and provide strong support for doctors to make more intuitive, convenient and accurate correction plans. Thanks to the development of computers and digital technology, dental digitization has gradually matured and begun to be applied. The oral scanner is used to scan the patient's oral cavity, collect information, and use image processing software to perform three-dimensional reconstruction, transform it into a three-dimensional digital model, store it in stl format and slice it, and then use light-curing 3D printing technology to print the model. Compared with traditionally manufactured plaster models, the use of light-curing 3D printing technology to make models takes less time and is more efficient. Compared with traditional plaster models, digital models have the advantages of small physical storage space, convenient storage, high security, less susceptibility to physical wear and damage, convenient and rapid data analysis, and efficient remote transmission.
PioNext scans the gypsum model through a three-dimensional scanner to obtain the stl file, and repairs and reconstructs the resulting file, and then uses light-curing 3D printing to print the obtained model. The linear measurement study with the gypsum model shows that: the use of 3D printing technology for positive The production of abnormal models is feasible and economical.
Scanner scanning technology scans to obtain the digital model of the tooth jaw, and prints the solid model through the SLA light curing rapid prototyping machine, uses the vacuum adsorption hot pressing film method to obtain a transparent corrector, and compares it with the corrector made from the plaster model , Proved that the dental model and plaster model obtained by SLA light curing rapid prototyping printing have no significant difference in the appliance made, and the concept of developing a transparent dental dental correction data management system is proposed. At present, the whole set of technologies is relatively complete from oral cavity scanning to data simulation calculation to model output. The use of light-curing 3D printing technology to make orthodontic models has gradually become the mainstream direction, and the actual needs of the manufacturing process have been met, and the technical requirements for doctors have been further reduced. Due to the large population of our country, the improvement of people's living standards, and the increasing emphasis on oral health and aesthetics, our country's orthodontic market has huge potential.
For light-cured 3D printed orthodontic materials, the materials must first be developed for the corresponding 3D printer; model designers and 3D printer manufacturers can make compensation adjustments to the model according to their own machines and matching materials, and the two can coordinate and match each other to achieve the best The printing accuracy. Secondly, in addition to accuracy, since the orthodontic model needs to undergo instantaneous high-temperature vacuum suction when the transparent braces are subsequently turned over, the material is required to have a certain degree of toughness and resistance to instantaneous high-temperature impact and non-deformation. Some denture
processing factories also require printing models. It can withstand two or more times of re-moulding, that is, the model should not be deformed or reduced in accuracy due to heating and force after the first re-moulding. Because the orthodontic cycle of a patient is generally more than one and a half years, it is necessary to print more than 50 sets of braces, so the use of orthodontic resin is relatively large. The combination of the field of dental orthodontics and light-curing 3D printing will open up a huge application market for light-curing 3D printing technology and materials, and will become one of the largest application areas of 3D printing.
3.2 Application of light-curing 3D printing in the field of dental restoration
Light-curing 3D printing technology has been applied in the field of oral restoration for some time. As early as 1994, Tomiu et al. used 3D laser scanners and charge-coupled cameras to collect silicone rubber impressions and trays to make upper and lower jaw impressions, and used light-curing 3D printing to make digital full denture bases with photosensitive resin. Light-curing 3D printing in the field of dental restorations is currently limited by the biocompatibility of materials and cannot directly contact the human body for a long time. It is mainly used as a transitional material, such as dental investment casting and dental restoration models.
At present, dental model resins are widely used in the dental restoration process, and the commercialization technology has been very mature. Most of the restoration models are concentrated in the denture processing factory for printing and casting. The hospital sends the patient’s oral scan data to the denture processing factory. After the factory optimizes the model data, the sliced model is printed using a light-curing 3D printer. The resin model is consistent with the shape of the patient's oral cavity. The doctor can perform simulated restoration operations on it, and make implants, crowns, etc. for the patient according to the shape of the model, and perform nesting operations on it, and then the teeth are completely matched. Planting into the patient's mouth greatly reduces the patient's pain and improves the efficiency of medical treatment. In addition to high precision in material properties, the repair model also requires that the model be non-deformable, high surface hardness, and wear-resistant during the use period, which meets the needs of doctors to repeatedly simulate repair operations on it.
With the increasing maturity of light-curing 3D printing technology and the invention and improvement of new printing materials, it is believed that the application prospects of light-curing 3D printing in the field of oral restoration will get better and better.
3.3 Application of light-curing 3D printing in dental surgery guides
Traditional dental surgery relies on the personal technical proficiency of the doctor, and requires a high level of skills of the doctor, which brings certain risks to the operation. The dental surgical guide can help the doctor to well control the implantation direction, angle, and depth of the implant during the operation, reduce the risk of the operation, reduce the operation time, and achieve the advantages of minimally invasive implantation without flaps. Traditional implant surgery guides mostly use hot-pressing film technology on plaster models. Although they can take into account the effect of upper restoration, they cannot precisely control the position of the implants. It depends to a large extent on the clinical experience of the doctor, and the deviation is also large. With the development of digital medicine, 3D printing technology has been widely used, and precision dental surgical guides have become possible. The digital dental implant surgical guide made based on the principle of this technology mainly uses metal powder, liquid resin, ABS material, PEEK material, etc. Laser-based SLS, EBM and other 3D printing technologies, equipment and metal materials are expensive, and the production cost of corresponding dental products is high. Even if it is used to make implants, it is not conducive to widespread promotion. In _ secondary consumption products such as preoperative implants The production of surgical guides is even more difficult to accept. Relatively speaking, 3D printing technologies such as SLA based on light curing have lower cost, high printing accuracy, and better surface quality of the printed parts. They are more suitable for making implant guides, but at the same time, higher material properties of dental surgery guides are proposed. Require. Dental surgical guides belong to Class I medical devices and need to pass biocompatibility testing. At the same time, they have higher requirements for mechanical properties, heat resistance, and sterilization resistance, which also adds greater difficulty to material designers. , Which greatly limits the clinical application and promotion of light-curing 3D printing. Therefore, light-curing 3D printed surgical guides are currently less used, and domestically produced materials are in urgent need of development. Light-curing materials that meet Class I medical devices are the key research direction and will certainly have a good market prospect.
Conclusion 3D printing has a bright future in the dental market
With the continuous improvement and improvement of 3D printing technology, the systemization of industrial production of 3D printers has become more and more perfect, the price of 3D printers has been decreasing, and the performance has gradually improved. 3D printing technology can improve the efficiency of material utilization and reduce the use of dental implants and dentures. The complexity and difficulty of the production of other precision items, as well as the advantages of promoting the continuous improvement and innovation of products. In short, as a disruptive technology, 3D printing has outstanding advantages in the highly personalized dental market, especially in the fields of dental restoration, dental orthodontics, and dental surgical guides, and has a broad market prospect.