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July 2009 | Dental Lab Products
Tech tomorrow

Pushing the boundaries

How far away are scientists from printing a ceramic crown?
Not far at all.

By Pam Johnson

David Rosen, PhD, holds his revolutionary new-generation inkjet print head that is capable of printing high-viscosity ceramic materials onto metal or ceramic frameworks.

No challenge is too tough or too complex for David Rosen, Ph.D., to tackle. Working in his research laboratory at the Georgia Institute of Technology George W. Woodruff School of Mechanical Engineering in Atlanta, Rosen and his team of scientists are developing high-precision, high-accuracy additive manufacturing processes that in the near future could produce a final product in industrial quantities. Using specialized inkjet printing technology and materials, Rosen believes he is close to developing the Holy Grail of dental technology…the ability to print esthetic ceramic dental restorations.

Rosen is not the only researcher on the quest to develop technologies that can print ceramics. But what makes his research unique is its scalability.

Unlike other 3D production processes such as selective laser sintering, 3D printing, fused deposition modeling, and stereolithography that are limited to a single material and print parts using a single laser beam, liquid binder, or melted polymer to solidify patterns, Rosen’s inkjet process has no such limitations. “If you want to print more, go faster, print larger, all you need to do is add another bank of print heads,” Rosen said.

Overcoming the obstacles

The ultrasonic droplet generation print head can handle a ceramic slurry with ceramic particles suspended in a liquid.

Custom IMD Project

This European funded and based project (www.customimd.eu) is committed to developing next-generation biomaterials and rapid manufacturing technologies by 2010 that will produce fully customized medical and dental surgical implants in 48 hours. The initial objective is to supply surgeons with craniofacial bone plates, lumbar spinal disc prostheses, and dental restorations based upon the clinical needs of the patient. This e-supply chain will be expanded to include other medical devices and is expected to reduce EU healthcare costs by 20%.

Inkjet printing is hardly a new technology. Developed in the 1960s, inkjet technology is most commonly recognized as that used in the desktop printer we have at home or in the office. The traditional two-dimensional inkjet process works by pushing a tiny jet of liquid ink out of a nozzle to form various sized ink droplets, either by applying heat or pressure to force the ink out of the nozzle and spray onto a substrate in a definable pattern.

It wasn’t until some 20 years later that manufacturers and scientists realized the enormous potential inkjet printing held for depositing a variety of materials other than ink. As the technology matured, it was soon possible to print complex three-dimensional geometries—such as the 3D wax printers currently used in the dental technology industry—to create intricate three-dimensional wax forms for casting or pressing onto metal and ceramic frameworks.

The biggest challenges inkjet technology scientists must overcome are the viscosity of the material being used and the size of the nozzle the material is forced to pass through. Commercial inkjet technologies used in dental applications currently print low-viscosity photopolymer resins that pass easily through the small nozzle heads. Printing ceramics, however, requires a thicker material that current inkjet print heads can’t handle.

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