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Is your scanner accurate enough?

by: Michael Stuart

Getting a precisely fitting CAD/CAM restoration begins with accurate digitization of the treatment situation. This is where the right scanner gives you the advantage.

Few would dispute that scanning technology has the edge over traditional casting methods when it comes to accuracy. An in-vitro study by Katsoulis et al. demonstrates the high accuracy of both laser and tactile scanners.1 Their research used gap measurement between the framework and the implant shoulder as a read-out of accuracy for ten-unit titanium and zirconium dioxide frameworks and showed median vertical gaps of 15 μm and 14-18 μm, respectively. This is a big improvement compared with the gap of 236 μm the authors measured for conventional casts.

According to the authors, the “misfit of the full-arch cast alloy frameworks is clinically unacceptable”, and laser and tactile scanners with CAD/CAM technology are the choice for those looking to "facilitate fabrication of highly accurate long-span screw-retained reconstructions made from zirconium dioxide."

Choose the scanner that’s right for you

It’s important to keep in mind that not all scanners are the same. When it comes to selecting the right scanner for your lab, it’s worth taking another look at the research. 

In a study assessing the accuracy of both the Procera and NobelProcera scanners the authors concluded and confirmed that both offer a level of accuracy suitable for use as an input for manufacturing fixed dental prostheses. It shows that the deviations in measurement when acquiring data with either device are just 11 μm, and can fall as low as 4 μm with repeated scanning.2  The study also shows that conoscopic holography is as accurate as a touch probe scanner within acceptable threshold limits (0,005 mm). 

The NobelProcera 2G Scanner

The linear route to great results

Do you know which technology your scanner uses? Our laboratory-based scanners have evolved since the early Procera touch probe scanner used for digitizing stone casts. Today’s NobelProcera 2G Scanner takes advantage of a technology called conoscopic holography.

Getting technical for a moment, conoscopic holography differs from techniques such as triangulation in that it reflects the laser in the same linear pathway to, and from, the scanned object. Known as ‘co-linearity’, this allows measurements of steep angles and deep cavities, so you get an optimized surface scan.

Though further studies are needed to confirm the predicted superiority of holographic scanners over tactile technology, dental professionals like Davide Riva, a Certified Dental Technician from Italy, are already experiencing the benefits:  "The NobelProcera 2G Scanner can work with an angulation that allows it to read every part of the model – even when you have a difficult scan situation."

“Better everything”

Greg Sederlin, President of Cal Ceram Dental Lab in the U.S. has also been impressed. He describes the accuracy and quality of digitization as “phenomenal” and has seen his lab’s output improve as a result, experiencing “better fit, better angles, better everything.”

Greg goes as far as to compare the change in quality between earlier Procera Scanners and the NobelProcera 2G Scanner as “the difference between looking at the moon through your eyes and looking at the moon through the Hubble Telescope.”

There’s a lot to consider when upgrading your scanner but, to paraphrase Greg, if you’re looking for accuracy that is out of this world, the NobelProcera 2G Scanner is for you.

More to explore

 

References

Katsoulis J, Mericske-Stern R, Rotkina L, et al. Precision of fit of implant supported screw-retained 10-unit computer-aided-designed and computer aided-manufactured frameworks made from zirconium dioxide and titanium: an in vitro study. Clin Oral Implants Res 2014;25(2):165–74.

Holst S, Persson A, Wichmann M, Karl M. Digitizing implant position locators on master casts: comparison of a non-contact scanner and a contact-probe scanner. Int J Oral Maxillofac Implants 2012;27(1):29-35