Dentistry Prepares for Its Close-Up

By Cindy Riley

JAW-DROPPING VIEWS (Click photo to enlarge) Cone-beam CT scanning lets dentists see teeth and surrounding structures in incredible detail, improving diagnosis and reducing invasive procedures.If you're interested in the future of dental care, wait 20 seconds. That's how long it takes the UAB School of Dentistry's new cone-beam computed tomography (CT) scanner to make a 360-degree image of a patient's mouth that takes in teeth, gums, bones, blood vessels, and sinus cavities.

"It's like a CAT-scan machine specifically made for dental and maxillofacial structures," says Richard Weems, D.M.D., M.S., who directs the maxillofacial imaging program at the dental school. "It takes several hundred images in short, small bursts of radiation, and special software puts it all together in 3-D."

Vision for the Mission

The new machine, one of only three in Alabama, has several advantages over traditional X rays. It produces images with a higher resolution at radiation exposure levels that are 30 times smaller. But the scanner's ability to view the mouth from every angle is what makes it such a powerful diagnostic tool.

"Dental implants are being placed more and more often today, and this equipment offers a look at the implant site that you can only get in two dimensions with conventional X rays," says Jim Broome, D.D.S., M.S., associate dean for clinical affairs at the School of Dentistry. "I see this becoming more and more popular as time goes by. The more information you have about where you're placing an implant, the more likely you are to have success."

The cone-beam scanner is also useful in preparing for oral and maxillofacial surgeries, Broome says. It can even provide orthodontists a very accurate virtual model of a patient's teeth and jaws without the time and expense involved in taking a physical impression.

"We've also had individuals with trauma and facial damage who've been helped," including a patient who took a hard fall out of a golf cart, says Weems. "His cheek hit concrete, fracturing the orbit of the eye and his cheekbone, and smashing into the sinuses. With this screening they were able to determine how to restore the damage from inside the mouth, without having to make an incision and remove a lot of tissue."

Free and Clear

Unlike the whole-body CT scanners commonly used by physicians, the cone-beam CT works while the patient is seated normally, much like a panoramic X ray. An estimated 60 patients have been scanned at UAB since the machine was installed last June.

"You see images as they are being taken, one at a time, with the whole head turning," says Weems. "The software gives you images from the side, front, and top to bottom. You can move back and forth and get ‘slices' that can then be put together. We can make printouts with the slices and put the information on disk, and the dentist can take it to his desk and review it all as he chooses."

Because of these advantages, Weems believes that dental CT will soon become the diagnostic standard of care for many complicated procedures. "You're getting 360 degrees of information, allowing you to re-create any image in any direction," he says. "I believe this is part of the future of dentistry."