Dr. Ove Peters

Rooting Out the Problem

Eerie Canals. Because VGStudio MAX can classify and segment µCT data sets by brightness or rigid density, Dr. Peters can create images detailing only the microcsopic root canals inside a tooth. He can rotate the tooth and view any cross sections he chooses (at left).

Volume Rendering Allows Differentiation

According to Dr. Peters, he started doing his first good imaging sessions in 2001 with VGStudio MAX, a sophisticated application for volume rendering of three-dimensional images. Compared with polygon-based 3D graphics, volume rendering is superior for anatomical study because it displays not only the surface structures of an object, but also discretely differentiates its interior structures. For Dr. Peters, this kind of visualization was essential in defining the microscopic canals of soft tissue located deep inside the hard enamel exterior of a tooth.

To create his 3D images, Dr. Peters worked with data sets gathered from shooting extracted teeth using a CT scanner in Switzerland. These data sets can sometimes be enormous files, up to tens of gigabytes each. “At the time, VGStudio MAX was the only software on the market able to process data sets larger than 1GB on affordable hardware,” says Christof Reinhart, president and CEO of Volume Graphics, developer of VGStudio MAX. “Initially, it was only available on Linux, which was very awkward and difficult to use,” adds Dr. Peters. “In essence, you had to be almost a computer programmer to handle the whole thing.”

Eliminating Time-Consuming Steps

But in 2002, Volume Graphics released a version of VGStudio for Mac OS X. Dr. Peters switched immediately. In addition to offering an improved user interface, the Mac OS X version allowed him to eliminate a number of time-consuming steps required by the Linux version. Today, Dr. Peters obtains his CT file sets from a server or on DVD and uses VGStudio MAX to import them into his dual-processor Power Mac G5 desktop system or his MacBook Pro.

“With the dual-processor Power Mac G5, I can run Volume Graphics with real dual speed,” he says. To render the 100 images for a circular run around a tooth, he says, it takes just several minutes.

A Variety of Visualizations

Using VGStudio MAX on the Power Mac G5, Dr. Peters renders data in a wide variety of ways, from basic cross-sectional views at any angle to 3D views in which he can spin a tooth around and view the root canals from any direction — even from inside the tooth. Because of its sophisticated ability to manipulate the data sets by both classification and segmentation methods, VGStudio MAX allows Dr. Peters to extract and display images of even the tiniest root canals that were undetectable before this kind of visualization was possible. And using data sets of a tooth gathered before and after treatment with various dental instruments, he can compare them, pointing out undertreated areas to address the causes.

So will this kind of technology find its way into the average endodontist’s office anytime soon? According to Dr. Peters, the method of scanning he uses wouldn’t be practical in a clinical setting because patients couldn’t tolerate the high irradiation doses and lengthy sessions needed to produce such high-quality scans. “However, µCT machines for clinical application have recently been introduced that produce images of slightly inferior quality compared to the laboratory applications,” he says. “The images are by far superior to everything that was produced in the clinic before. In the near future, with further improvements of hardware and software, these scans will likely be taken from all patients in the dental chair.”

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