Name: The Future of 3D Printing
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Since the 1990s, when the first non-precious metal bases were produced using 3D printing methods, the 3D printing technology has established itself as a modern production process.
Today, various plastics are also available as high-performance materials. Many users are already considering supplemental extensions and thinking about investing in this technology.
3D printing is an additive production process, contrary to subtractive methods, for example computer-controlled milling or grinding ceramics or the machining of non-precious metals or titanium. However, many analogies can be discovered and used as advice when one is considering implementing 3D printing.
3D printing in dental technology
First of all, one has to be aware that additive manufacturing is a trusted method. Ordering dental technology items that have been industrially produced using the 3D printing technique has been common for many years.
Among others, one is familiar with selective laser melting, selective laser sintering (SLS), direct metal laser sintering (DMLS) or lasercusing: Here crowns, bridges and denture bases (“digital model casting bases”) are made out of non-precious metal dental alloys.
Non-precious metal powder layers are applied and are briefly melted onto the defined places with a laser beam in using a high amount energy. In this way following a construction plan, which was created on the monitor for example using the CAD process, high-precision dental technology items are produced.
Stereolithography is a also a familiar 3D printing method. Models, splints and drilling templates can be produced using this method. The principle is similar to laser sintering, however whereas in the latter the applied material is melted on layer by layer, in the case of stereolithography the light polymerization of plastic is implemented.
In order to be able to assess the 3D printing method more efficiently in future, it is worth taking a look at the early zirconium oxide technology. Initially large industry machines produced dental technology items and the laboratories were able to order them from external service providers. Later, in-house production also became attractive. In this way, a combination between central manufacturers, cooperative laboratories that carried out contract manufacturing for other laboratories in order to exploit their own systems to the full and laboratories that offered round-the-clock own production, who also additionally outsourced parts of the production, established itself.
Currently, some laboratories are asking themselves about the optimal implementation of 3D printing: Drilling templates, different splints, dental technology models, individual impression trays and plastic base casts for the metal cast depict the most frequent indications.
Whether they are ordered from an external service provider or produced in one’s own firm, is determined by the amount of the orders to be expected and the speed required by the customer, where own manufacturing principally allows immediate production.
The recent IDS 2017 exhibition demonstrated the technologies available in 3D printing and how to invest in them.
Extended range of printing methods
In addition to the methods already mentioned, among others the so-called multi-jet technology (detailed work up to precisely 16 micron), the fused layer techniques (fused deposition modeling, FDM; fused filament fabrication, FFF) and the mask exposure method prove to be interesting.
The multi-jet technology works following the principle of the “inkjet printer”. For example, (almost) two-dimensional layers of powder are rolled out and then imprinted with bonding agents exactly on the places where the dental technology item belongs according to the construction plan (virtual model), the non-bonded power can be simply removed.
The material used is either glass or metal powder, whereby with today’s current state of technology only the metal powder is suitable for the production of solid objects, because to this end after the printing process, a sintering and an infiltrating step to fill up existing cavities have to subsequently be carried out.
Alternatively, you may print two-dimensional photopolymers according to the construction plan and lets them harden so that the item is formed layer by layer.
Using the layer melting technique one extrudes for example waxes or plastics out of a nozzle or applies the material drop by drop, once it cools down it solidifies, then the next layer can be applied.
Finally, the mask exposure method works similar to the well-known stereolithographical technique. The decisive difference – instead of using a laser, the plastic is hardened with the aid of a UV LED lamp.
Printing of tooth-colored table tops and temporaries
One of the big hopes for dental 3D printing is the optimized coloration of materials, for example of high-performance plastics. The experiences of the subtracting methods have proven that zirconium oxide has initially only been implemented with a veneer covering. More recent versions with a higher translucency are on the other hand used monolithically.
When complete dentures are produced digitally in a working step in the laboratory and the tine-consuming procedure is limited down to two dentist appointment for the patient, why not printed table tops and temporaries soon too?
Case studies are already showing now: An implant-supported top jaw complete denture can indeed be made out of PEEK (polyether ether ketone) using the 3D printing technique and plastic veneers lend it an attractive appearance. PEEK (polyether ether ketone) could also become one of the base materials of the future, especially since in combination with a veneer composite it displays similar characteristics to veneered zirconium oxide.
Digital workflows make 3D printing attractive
In addition to new materials, the possibility of integration in the digital processes also provides a boost. For example, the 3D printing of dental technology models could develop into a frequently used option as a result of the further distribution of intraoral scanners.
3D printing offers extraordinary potential, according to the Association of the German Dental Manufacturers (VDDI). This also applies to the closer collaboration between the dentists and the dental technologists with digital workflows.
The backward planning in implantology is an example of this, where 3D printing creates a concrete additional option in the form of the production of detailed drilling templates at the laboratory.
This article was published in DPN3/2017 issue. To request for the publication: http://dentalnetasia.com/dpn-issue-32017