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3D Printing: How a Star Trek Fantasy has Become Reality for the Dental and Orthodontic Professions by Pamela Waterman

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Star Trek had it right: though not quite yet a push-button process, creating physical objects via 3D printing (additive manufacturing) is a real and awesome option for many dental and orthodontic applications.

Maybe you’ve seen Jay Leno’s Garage on YouTube where Leno enthusiastically describes how he “printed” a custom plastic part to help restore his 1907 White Steamer car.1 Or perhaps you’re acquainted with the basics of rapid prototyping as an alternative to casting for producing dental copings and aligner molds. Either way, you’ll find the technical advances in this amazing field offer more and more choices for creating parts seemingly out of nothing. It’s not exactly a Star Trek replicator system, but the advantages for dentistry and orthodontics are huge and undeniably cool.

Additive Manufacturing 101
Remember how watches were just watches until digital versions came along? And suddenly you had to differentiate between digital and analog versions? A parallel situation now exists for building parts. Whether making titanium screws or turbine blades, machining an oversized chunk of material really implies subtractive manufacturing – you or a computer-guided tool, cutting away excess until you get the desired shape. The process can be very quick, it produces highly accurate parts and it works with a great variety of materials. However, achievable geometry is limited and costs can include large amounts of wasted material.

Conversely, additive manufacturing (AM; originally, rapid prototyping) starts with just a bit of raw material, generally in sheet, liquid, filament or powder form (Note: see sidebar). Guided by a 3D computer-aideddesign (CAD) model as a pattern, AM equipment builds parts up layer by layer, using lasers, heat or binders to merge the material, creating a physical solid with very little waste (and much of the raw material gets reused). The process can produce a single prototype or one custom piece, a number of very different final parts, or a thousand almost-identical parts.

The first AM method was developed in 1986 at 3D Systems, a company originally out of California and now based in South Carolina. Dubbed the stereolithography apparatus (SLA) approach, this system moved a precisely controlled laser beam to cure or harden liquid resin layer by layer into the desired shape. These first plastic parts had somewhat rough, ridged surfaces and limited durability, but their potential launched an industry.

Since then, dozens of engineering companies and university research groups have taken their own creative and widely divergent approaches to “growing” or printing a part. Although the term 3D printing originally referred just to one design configuration (where a modified Hewlett-Packard inkjet printer sprayed a binder onto powdered material), the phrase has become a common term for all types of AM. It presents an easily understood vision of transitioning from paper-and-ink 2D copies to solid, hold-in-your-hand objects.

Copings, Bridges, Models and Guides
Where is 3D printing used in dentistry and orthodontics? Possibly right in your own practice, depending on your choice of dental lab or your involvement with Incognito or Invisalign treatment. For example, drilling guides for implant surgery are now printed in plastic directly from digital scans, on AM systems by EnvisionTEC and Z Corporation (ZCorp, now part of 3D Systems). EnvisionTEC’s system uses UV light to harden liquid photopolymers, while ZCorp equipment uses the HP system described above.

SLA systems from 3D Systems are currently used to create high-resolution epoxy-based models from digital scans of individual teeth, arch sections and full arches. By e-mailing digital files as the basis for these models, labs replace the plaster versions and save on shipping time and cost.

Dental copings are one of the major success stories for AM applications, with two general types of equipment playing a key role: those that print wax-up models for traditional casting (indirect method) and those that create final metal parts, completely bypassing the casting sequence (direct metal method).

The indirect production process is a logical variation on creating casting models. Instead of working with wax to craft a hand-shaped tooth over a plaster tooth stump, a technician uses scan data and dental software to design a CAD model of the patient’s crown. That file then drives an AM system to create the coping shape in a plastic that works just as well, if not better, than wax in the casting stage. Three companies that market AM systems with this capability are 3D Systems, EnvisionTEC and Solidscape (a Stratasys company).

Solidscape, a pioneer in finely detailed wax-up parts in both the jewelry and dental fields, employs yet another fabrication method called drop-on-demand. Its systems deposit fine droplets of thermoplastic with excellent ash-burnout properties, and its proprietary Smooth Curvature Printing technology is recognized as an industry stand-out for creating fine finishes.

In the direct metal arena, both 3D Systems and EOS, a German manufacturing company with a strong U.S. presence, offer systems that melt (sinter) powdered metals such as cobalt-chromium-molybdenum-based super alloys into full-density metal parts, eliminating the wax/casting steps entirely. The process, generally called laser sintering, produces batches with hundreds of copings at a time, each custom-shaped according to a scanned patient model. Medically certified for in situ use, the metal copings serve their usual role as a base for porcelain coating. The final result is a fast, cost-effective, high quality crown that fits with minimal in-chair rework. EOS has an installed base of more than 35 dental EOSINT M 270 systems worldwide.

Aligners, Screws and More
Perhaps the best-known dentistry-related AM application is the creation of molds for thermoforming Invisalign aligner trays. SLA machines from 3D Systems play a crucial role in automating the aligner production process at Align Technology’s facilities. Creating each patient’s set of individualized trays on 3D printed molds made the process economically feasible. The company recently said that its 35 SLA systems manufacture 40,000 parts a day for a yearly total of eight to 10 million pieces.

Clearstep Laboratories is a U.K. company that also produces clear, removable orthodontic aligners based on digital technology. Clearstep aligners are vacuum-formed over 3D printed models made on Objet Geometries AM systems. Objet equipment uses PolyJet polymer jetting technology, using UV light to cure finely detailed parts built in layers as thin as 16 microns. This smooth finish on the molds translates to an easy-to-clean surface on the aligners.

Orthodontic treatment via lingual braces is yet another specialty field enhanced by AM technology. Lingual brackets, with their smaller profile and fine slots, demand particularly exact manufacturing; ideally, customized to the patient and each individual tooth. T.O.P. Service für Lingualtechnik GmbH, a 3M Unitek company in Germany, has met these challenges by using Solidscape equipment to create investment casting patterns for its Incognito lingual systems. The low-temperature burnout and smooth surface finish of the wax-like models is ideal, and ±5 micron-layer build precision eliminates the step of electron-discharge machining (EDM) each slot.

Lastly, titanium dental implant screws produced on directmetal AM systems offer the benefits of great biocompatibility, excellent mechanical performance and high bone-ingrowth potential. The ability to control the laser-sintering process allows production of a hybrid implant structure with a fully dense body and porous surface morphology. The latter eliminates the need for coating and offers enhanced bioactivity. Without the need for tooling, many types and sizes of screws can be produced in one run.

AM-based Dentistry is Here to Stay
Lee Dockstader, vice president of 3D Systems dental segment, says that many factors are coming together to make this an excellent time to use AM. Commenting on general improvements in indirect manufacturing, he says, “The manual way of taking impressions has many variables, while intra-oral scanners remove the variables. There’s new software, there’s impression scanners, and the big players use stereolithography to produce the models (for building a crown, etc.) When they take a crown off the model, it fits every time.”

EOS notes that a dental technician using a conventional casting process can only produce about 20 dental frames per day, while one laser-sintering system creates approximately 450 crowns and bridges in a 24- hour run. What does this add up to? The company recently announced that in the past year alone, dental labs used their AM equipment to produce more than 1.5 million direct-metal copings and bridges. Reducing processing time allows the technician to concentrate on the value-added tasks of aesthetic and function-oriented ceramic veneering.

Looking a bit into the future, researchers at Washington State University have used a ProMetal 3D printer to create a bone-like scaffold structure for supporting growth of immature human bone cells. Headed by Dr. Susmita Bose, this four-year effort (involving chemistry, materials science, biology and manufacturing) has shown promising results with in vivo tests on rats and rabbits.2 The addition of zinc and silicone more than doubled the strength of the main printing substrate, calcium phosphate.

Dental and orthodontic applications have truly validated additive manufacturing as a standard and efficient production option. And who can deny the pure Star Trekky appeal of being able to say, “My braces were made possible by 3D printing?”
Author's Bio
Pamela Waterman is the president of Metal Mouth Media, a publishing company dedicated to “taking the bite out of braces” through specialty cookbooks, articles, Web resources and workshops. She has been a spokesperson for the American Association of Orthodontists and is the creator of the new “Braces-Friendly” Seal of Approval. Based in Mesa, Arizona, Waterman has more than 25 years of experience in engineering and writing, is a contributing editor for Desktop Engineering magazine, and is the author of four books including the award-winning Braces Cookbook series. She can be contacted at pwaterman@metalmouthmedia.net.
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October 2025
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