An Introduction to 3D Printing and Laser Sintering
Inside Dental Technology delivers updates on digital workflows, materials, lab techniques, and innovation in dental technology through expert articles and videos.
April 1, 2013
Volume 4, Issue 4, April 2013
Page(s):
Nine years ago when working at his father’s dental laboratory in Los Angeles, the author purchased his first 3D printing system. At that time, he and his father had this crazy idea of using a 3D printer to help with production. Armed with a computer science degree and tapping into his father’s dental experience, the author thought implementing the technology could work. But it quickly became apparent that they were in over their heads. However, it was a fascinating—and very expensive—learning experience. They managed to cobble together a system with a Z-Corp printer (www.zcorp.com ), a commercial scanner, and industrial CAD software to tie the two together. Thankfully, things have come a long way since then in terms of price and usability. With the technology available now, almost every operation in the laboratory can be optimized or improved with 3D printing.
There are a plethora of articles and blog posts about using 3D printers for making castable or pressable restorations. Currently, this is the mainstay of 3D printing in the dental space. Here’s a quick review for those unfamiliar on how to use a 3D printer: Scan the stone model, design the restoration with CAD software, print a wax pattern, invest it, burn it out, and cast (or press). Printers from almost every manufacturer on the market can accomplish this. There are machines from EOS (www.eos.info) and Concept Laser (www.concept-laser.de) that let you print directly to metal to avoid the whole casting process. However, the final product is still a metal substructure or a full metal crown. This is a great use of the technology since crown and bridge represents such a large segment of the dental market. It also makes financial sense for companies to target this space first. However, this discussion focuses on some of the more esoteric areas of 3D printing in the dental field, including some new technologies and new materials that have not become quite as mainstream as castables (Figure 1).
Almost every company interviewed for this article stated that the most significant advances in the 3D printing will come from newer materials. Not every company could disclose research and development projects, but a few were willing to share products still in the development process.
Solidscape (www.solid-scape.com), a Stratasys company, recently introduced a new material, 3Z™ LabCAST, which allows for better castings and is less brittle than the company’s previous-generation material. This also goes along with its new 3Z™ Lab printer that launched a few months ago. Less brittle is better because of the delicate nature of the parts dental professionals work with and how prone they are to being adjusted or dropped (Figure 2).
If you think milling zirconia is the only way to get a zirconia restoration, then EnvisionTEC (www.envisontec.com) may surprise you later this year. If you want to be able to print temporaries, the company has a material called E-dent that is FDA-approved and can last for up to a year in the mouth. This allows the dental laboratory to design a set of temporaries with your CAD software, and then produce that exact same morphology when they come back in for the final product (Figure 3).
Almost every 3D printer on the market requires a support structure, with only a few not requiring it for specific applications. The support can be made from the same material as the part or it can be made from a separate material. In a process called post-processing, the support must be removed after the part has been printed, after which the part must be cleaned up.
Some post-processing requires cutting of the support material and then finishing the part down, such as with the EOS, EnvisionTEC, Concept Laser, or DWS (www.dwssytems.com) machines. The degree of difficulty in removing supports varies from process to process. Some require cutting or tools, while others break away clean. Still others require that the support material be removed with an oven, solution, or some combination of the two such as 3D Systems (www.3dsystems.com), Solidscape, and Objet Dental units (a Stratasys Company) (www.objetdental.com). In an ideal world, post-processing would be as simple as dropping the part into water to dissolve the support material. Stratasys’s support material is slightly water soluble, but the technician must still use a water jet to remove everything. So while some get close, no one is at the point of effortless support removal.
If the system allows for it, material development can come from sources other than the manufacturer. Argen Digital has recently started producing copings from its NobleCrown NF material on SLM equipment, and is working on launching a white high noble in the second half of 2013. This is significant because SLM equipment only comes with the ability to produce non-precious copings out of the box. For Argen Digital to get to this point, it took a team of metallurgists and lengthy research—not recommended for just any consumer to try. In addition to semi-precious copings, Argen Digital has launched its Digital Captek™ product, removing a large portion of the labor required to make Captek copings. Using the technology, a die is printed then 80% of the work required for the copings is completed at the Argen Digital facility, which then ships the copings to the laboratory for final finishing.
Bego is also using SLM technology in their production center to offer laboratories non-precious chrome cobalt Wirobond C+ copings and bridge frameworks and announced at the recent IDS 2013 the introduction of SLM noble alloy to their line of offerings. In addition, the Bego production center can supply customers with 3D wax printed copings and frameworks for use with conventional casting techniques.
Dale Dental has also entered the 3D digitally manufactured metal alloy arena with its Fusion Laser restorations. Available in high noble, noble, and base alloys, the substructures can then be layered using conventional layering techniques.
One of the larger players in the dental 3D printing market worldwide is 3D Systems (www.3dsystems.com). The company produces the line of ProJet™ printers that can be used for a variety of dental applications. It is best known for the DP3000 printer, which allows dental laboratories to print a wax pattern. However, the company has another machine in its lineup, the MP3000, which is used for printing models and drill guides. Until recently, most drill guides have been limited to larger companies that had custom software and invested in very expensive equipment. However, when the MP3000 is paired with open drill guide software, anyone can start producing high-quality guided surgery templates (Figure 4).
Although Stratasys is probably best known for its model material, the company also has a line of Eden™ printers that can be used for the same purposes (Figure 5). Both the Eden and ProJet operate on similar technology, spraying down a layer of light-cured polymer and then passing over it with a UV light to cure the material. EnvisionTEC printers operate on a slightly different principle, but the company does have a material that can be used for surgical drill guides as well. All system materials have been proven to be biocompatible and are suitable in the oral cavity, so the decision about which system to use comes down to budget, quality of support, and ease of use.
What if dental technicians wanted to have their own custom implant to go into their surgical guide? Leader Italia (www.leaderitalia.it/en), out of Italy, is doing just that with its EOS machines. Because it manufactures each implant to order, it designs the size and porosity of the implant to fit the indication and patient. Other companies are using the EOS equipment to print implant abutments, which are then finished with a milling machine. With the two processes paired together, a completely customized implant solution can be provided from a single piece of equipment.
Implants are a popular commodity right now and much focus is being placed on them. But what about something more traditional? Dentures, both partial and full, are seeing increased usage in the 3D printing arena. EOS is launching a partial framework solution using its DLMS (direct laser metal sintering) technology. The partial is direct laser melted, meaning that there is no waxing and casting required. Once complete, the supports need to be removed and the parts hand polished. The savings in terms of time are obvious—although cost per part does need to be evaluated.
For technicians who want to use 3D printing for full dentures, solutions are coming onto the market this year. 3Shape (www.3Shape.com) has already launched its Denture Design software, a key component that was missing, to enable laboratories to get into digital dentures. This means that the other CAD vendors should be quick to follow. Once technicians design their digital denture, there is equipment from EnvisionTec that has been shown to print gingival denture material, and eventually it will be able to print the teeth as well. For the time being, technicians can pair the gingival printed base with stock denture teeth or mill out denture teeth from a suitable material (Figure 6).
Not all improvements come in the form of new materials or new indications. Providing access to 3D printing for those who could previously not afford it is, in the author’s opinion, a huge step forward.
The first generation of 3D printing equipment was focused on larger business operations like Sun Dental Labs. However, coming out are smaller machines that provide access to more people. Solidscape is already in this segment, with the 3Z Lab that retails for around $25,000. Its focus is on ease of use and one-touch operation. The only disadvantage is the build time. However if you are not a large volume producer, this may not be an issue at all.
EnvisionTec has a new small footprint product, the Perfactory Micro DDP, which allows the printing of patterns for casting, pressing, or temporary restorations. Ron Snyder, business development manager for EnvsionTec, stated, “We feel that the small labs have been passed over by equipment manufacturers. To address that growing need, we want to offer what we feel is a gateway piece of equipment.” The equipment is priced in the right range, at $16,000, and comes with a two-year warranty, as opposed to the one-year warranty offered by most other companies.
There may be a day in the future when a 3D scanner and printer are as commonplace as a porcelain oven. To get there, manufacturers will need to make some progress on the ease of use, reliability, and price point. But the majority of companies interviewed are working toward that goal.
Should technicians buy a piece of equipment based on what it could do in the future? Definitely not. The author advises staying away from the bleeding edge of technology. It is interesting to see what might be coming to the market, but the first generation of any new equipment or material rarely goes as planned. Find out which 3D printers your peers have used and ask what worked for them. Going with the more established processes will make life easier for you when you need help.
After you have put together a short list of equipment, evaluate the quality of support and ease of use. When the company sells direct, you really only have one option for support—the manufacturer. EnvisionTec, EOS, and Concept Laser, all sell direct. When buying from any of them, make sure to check around for laboratory owners who have already purchased a system to give you honest feedback about the quality of help they are receiving from the vendor. With 3D printers, you are locked into buying all your material from a single source, again, the manufacturer. Very few of the systems accept material from another manufacturer, so the company that sells you the machine is also your only option for material support. The only exception to dealing direct is 3D Systems, which has a reseller network for sales and support. This presents the challenge of finding a good reseller that understands the dental space. On the plus side, the resellers need to compete for your business. CadBlu (www.cadblu.com) is a reseller that has an excellent reputation with 3D Systems and Solidscape equipment, if you want to look at both machines. Even though 3D Systems does not sell directly to the end user, its Projet 3000 and Projet 3500 machines are still locked into only accepting its materials.
If the machine is easy enough to use and maintain, it won’t require much support help. No one wants to keep an engineer on staff or go through extensive training to know how to operate and fix your 3D printer. One-touch operation, easy material loading, and simple maintenance are what should be demanded of any 3D printing system dental professionals are considering. Solidscape is promoting this as an advantage of its 3Z Lab system. It has a one-touch operation and even remote monitoring of the printer by its support team, who can see if anything ever goes wrong with it.
All manufacturers interviewed were asked if 3D printing would ever replace milling in the dental space. Every single one responded with a resounding “no.” The two technologies will continue to exist side by side with neither one taking over. There are just certain things milling can do that printing cannot and vice versa. This is something to keep in mind if anyone ever promises that their 3D printer can do everything you might ever need.
In the author’s opinion, the ultimate goal of 3D printing is to produce the final restoration straight from the machine with a simple cleanup process. Achieving this with no sacrifice in quality and multiple materials could lead to a “lab in a box,” which is both exciting and scary. However, that is quite a few years away.
Even though it has been 10 years since his first 3D printer purchase, the author still remembers printing his first casting mold and trying to make a coping almost a decade ago. It is an incredible experience when you make your first restoration with this new fabrication technology, and it is something dental technicians should experience someday. To try out 3D printing, the author highly recommends contacting an outsourcing partner that already has the equipment or seek out a dental show where the equipment will be on display.
Chuck Stapleton is the vice president of global operations at Sun Dental Labs.
