Digital 'impressions' better than molds

By Wayne Laepple
The Daily Item

September 30, 2008 05:22 am

— LEWISBURG -- Dental assistant Jennifer Miller used to hate taking dental impressions. Now, she enjoys doing it.
Dental impressions are necessary for a dentist to be able to make crowns, bridges, dental implants and onlays. The impression is a replica of the teeth so a model can be made.
"I used to hate taking impressions," Miller said. "It was messy, it was uncomfortable for the patients."
She described mixing up batches of alginate, a plaster-like material that was placed in a stainless steel tray and inserted into the patient's mouth. The patient had to sit with this awful-tasting, cold "goop" in their mouth for two to three minutes.
"Some people had a real problem with it; it made them gag," she said. "Sometimes it would get all over them."
What's changed for Miller and the other assistants in Dr. David Robinson's dental practice is the arrival of a digital impression system they've nicknamed Rosie, after the robot in the old Jetsons television cartoon show.
The $21,000 Cadent iTero system uses advanced digital technology to allow dentists to transmit information to a dental lab to prepare the necessary molds to make a replacement tooth or teeth.
No more goop, no more cleaning and sterilizing trays, no more mess.
Using a probe with a tiny camera at the end linked to a computer screen by a cable, Miller makes the digital impression following verbal instruction from Rosie's feminine voice. It uses digital imagining technology to develop a three-dimensional view of the teeth.
Once the image is completed, in just three or four minutes, it can be manipulated on the screen with a mouse.
After Miller produces an image of the teeth opposite the area to be repaired, Dr. Robinson prepares the tooth that is to be repaired or replaced and then uses Rosie to make a digital image of that jaw on the same screen Miller used minutes earlier. He views the final image of the opposing teeth to be sure the replacement tooth or teeth fit perfectly.
Then he opens a form on the computer to write a digital prescription, and after he's checked it, he presses the "send" button and the virtual impression is transmitted to Cadent in Carlstadt, N.J., where a technician prepares the plaster model which is sent to a dental lab in Utah where a porcelain tooth is made.
The whole process, from the time Miller makes the initial images to the time Dr. Robinson punches the "send" button, is less than 15 minutes.
"This system eliminates the variables," said Dr. Robinson. "The result is a better fitting for the restoration, and the system is very versatile. We can do multiple teeth at one time."
Before the arrival of the Cadent system, the assistants had to carefully pour plaster into the hardened impression and ship it, along with a hand-written prescription, to the lab. The impression could be lost in the mail, and they were sometimes affected by changes in temperature, he said.
Robinson is enthusiastic about the system, he said, as he displayed an eight-tooth bridge he built for a patient.
"The man told me he now has a rock-star smile," Robinson said.
There are limits to what can be done with the Cadent iTero, Robinson admitted. It's only suitable for fixed restorations, so it can't be used to build full or partial dentures.
"We still have to take impressions for them," he said.
There just is no down side to Rosie, said Miller.
"It's easy to use, it's easy to care for, it's quick and painless," she said. "The patients love it."

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