Ceramic prosthesis are widely used because they have better biocompatibility and are more aesthetic than metal. It is also true that resin teeth might have less flexural strength and hardness, as proven thus far.
However, they do not cause abrasion of the antagonist teeth, and they are light, and have superior fit to the marginal area than the ceramic prostheses. The adhesive method used in resin teeth is the only one that is chemically compatible with the bonding agent. The other materials out there can only be worked with mechanical and physical bonding, and even though the strength of these materials are not bad, they fracture or a piece of them falls off when an impact is concentrated on a specific area. So far, since resin has a weak flexural strength, it has been insufficient to be used as a permanent crown, despite its good qualities. However, we have recently developed a synthesis method that can make the flexural strength of light-cured resin even higher than that of ceramic and have this very method acquire KFDA Level 2 as well as CE Class II, and now it is used for clinical cases. A paper published abroad states that resin prostheses are more resistant to average loads than ceramic prostheses if their thickness is bigger than minimum. Especially for chairside clinicians, 3D printed prosthetics are the most optimal one for restoration and indication from prosthetic treatment, conservative treatment such as inlays, and immediate functional implants. Now, we have the strongest material in this area with our own technology and we are expanding our business to overseas.
According to a published academic paper, although zirconia exceeds 1000MPa, its structure gets deteriorated by the intraoral moisture, and after one year, the initial strength worsens much.
The all-ceramic series used for chairside CAD cams such as lithium disilicate also shows 190MPa and only through crystallization they appear 360MPa. All materials mentioned are brittle and they are expressed as Bi-axial Flexural Strength. (Our materials appear to have average 360Mpa when proceeding with the same test)This is almost the same level when calculated with the general method of flexural strength, and compared to adhesive strength, it is much superior to all-ceramic.
Resin-based composites and hybrid blocks that were released in the past had poor water resistance. Like acrylic and methacrylate, most of them were focused on rigidity to increase flexural strength. It is a vulnerable structure to water because of its weakness due to its linear form of combination like a cellulose structure. In this case, it is difficult to combine the elastic structure, so in order to compensate for it, inorganic fillers like ceramics are mixed. Nevertheless, water resistance did not improve to the level of ceramics, rather saliva and food penetrate the restoration and cause odor, plaque, and discoloration. The water resistance of our material has reached a technical level that is 50% less than the 40 micrograms/cubic mm standard of the Ministry of Food and Drug Safety, and we plan to further strengthen it through this research project. Improved water resistance is fundamental for antibacterial treatment and antifouling aesthetics. We’re trying a new way to suit the nature of the assignment. Among crystallized glass, 45S5 is not biodegradable, and antibacterial properties of crystallized glass have been reported. Therefore, by using such antibacterial ceramic powder as a nano filler, it can sufficiently increase water resistance even in the state of a 3D printer material backbone. It will be possible to develop organic-inorganic hybrid high-strength aesthetic prosthetic materials, rather than simply mixing viscosity control and surface modification considering the optimal ratio.
In the past, thermoplastic resin teeth and hybrid teeth were not varnished with their own constituent material, so it was difficult to increase the surface lubricity, and ceramic materials had the inconvenience of undergoing a sintering process for staining. 3D printing method can easily enhance aesthetics through masking techniques and UV curing that apply denture coloring techniques to the surface. Also, it can create fast curing within one minute. By further advancing these technologies, the product can be even more perfect.
You can have great advantages in terms of system introduction price, functionality, and clinical use. Since a clinician is not able to wait for the sintering process chairside, most of the prosthetics are made using crystallized materials. Unlike pre-sintered zirconia, because a material with very high hardness and high brittleness must be used, it is possible only through wet grinding, and not general milling. Unlike milling processing, grinding processing requires wet processing and has a complex equipment structure, as well as higher rotational power than the spindles and other motors used in dry processing, leaving no choice but to use expensive equipment. Grinding burrs are also expensive, and need to be replaced after processing about 20, and many auxiliary materials such as lubricants are necessary. All of these parts eventually get passed on to consumers as a cost burden. However, unlike such grinding machines, the printer makes little or no noise, and the cost or introduction price is almost 1/10. In addition, since the material cost is more than 1/30 cheaper than all-ceramic, it has an absolute advantage in terms of cost. In terms of functionality, the existing all-ceramic requires about 20 minutes of grinding and processing time per piece, and additional post-processing is required. However, if it is a bridge number 3 rather than a single prosthesis, or if there are multiple restorations such as inlays or laminates, more time is required serially in proportion to the number. After the grinding process is finished, crystallization is performed for more than 20 minutes in a dedicated furnace with a built-in vacuum pump, followed by separate staining and additional sintering to enhance aesthetics. And again, because the contact surface of the adjacent teeth is trimmed or set in the patient through post-processing, it is difficult to manufacture multiple inlays, and an important implant SCRP prosthesis than an ideal single tooth, a bridge that is not an inlay. With a 3D printer, it can be completed in 20 to 30 minutes regardless of the quantity, so you can finish the production regardless of whether it is an easy shape or a difficult shape, and if you add about 20 minutes to the post-curing process, you can have the setting for your patient right away. Of course, unlike all-ceramic, this process does not incur additional costs. There is also a big difference in terms of clinical use. In cases where it is difficult to observe intuitively, mainly in the posterior part of the distal spots and in the subgingival region, it is often impossible to create a smooth interface required by CAD/CAM when preparing teeth. Therefore, in the case of all-ceramic, it is difficult to reproduce perfectly due to the limitations of the tool shape. That is why mostly Supura margins are required. However, there may be cases where the gingiva is retracted or the color of the protruding boundary surface changes in the future, which is not aesthetically pleasing. Then, since the ceramic is not chemically bonded, the inside of the prosthesis is etched with hydrofluoric acid solution, and additional primer or adhesive products are necessary. That is why more staff are needed at the chairside, and the chair time for both patients and hospital staff inevitably increases. Prosthetics made with 3D printers can easily reproduce the marginal area with many concavities and convexities, and during inlay treatment, 3D printing reproduces curves that the milling machine burrs could not make, so dentists can obtain stable results while maintaining the existing inlay preparation method. And since it shows a homogeneous effect through bonding agent and chemical combination, it can prevent fracture if it is installed with a flexural strength of 220MPa or higher. It has many other advantages, so now most major dental companies have developed 3D printers, and experts predict that a new market will be created in the next few years.
Korea's Ministry of Food and Drug Safety standards are also very strict, and many biosafety tests are conducted. Basically, physical and chemical tests include flexural strength, bonding strength, natural light sensitive soil, water absorption, solubility, etc., and biological safety tests consist of cytotoxicity grade 0, acute systemic toxicity test (Oral), oral Mucosal irritation test, sensitization test (LLNA), and genotoxicity test. Europe is even more strict and conduct bioburden test and transplant test, so if a material fails any of these tests, certification will not be granted. While preparing materials that are currently on the market, we have accumulated deep experience in this field and have the ability to prepare materials without problems in the safety part. By developing materials that are currently on the market, we have accumulated experiences in this field and have knowledge and expertise to create materials that do not have any problems in safety.
There are many 3D printing material makers, but only a few companies around the world directly synthesize oligomers with raw materials. Most people buy oligomers from a market and adjust the blending ratio with appropriate monomers. However, in this way the technical hurdles are very high to make a material that is elastic, strong, water-resistant, and safe. Since most of the materials that are made hard have a benzene structure, browning occurs when the initiator is decomposed incorrectly, and this browning darkens the color, so adding a lot of pigment limits aesthetics. On the other hand, our technology does not cause browning because we synthesize oligomers and high-molecular-weight cone polymers as well as a versatile and elastic structural backbone. Therefore, since light transmittance is expressed, less pigment is needed, and the aesthetic effect is further enhanced, enabling color expression that is higher than that of ceramics. In addition, it has high heat resistance, so there is no problem even if it is treated through autoclave sterilization. Our technology made our material the only material exported to global companies among domestic companies. Going Through this task we will further advance in organic-inorganic composite materials and the world's first non-sintered high-strength material, so it can be a world-class product.
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We like to create specialized materials. by Graphy Inc
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