VOA慢速英語: 機(jī)器人幫助牙醫(yī)治療病人

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Technology Reduces Time in Dentist’s Chair

For years, robots have helped doctors perform operations with greater safety, speed and exactness than by using hand-controlled instruments. Now, one such machine reduces the time it takes to make dental crowns. This procedure can repair a damaged tooth in just about two hours.

Years ago, several long visits to the dentist were required to manufacture a dental crown. And between visits, the patient had to wear a temporary crown – a small, hat-like cover that encircles the tooth. During that period a technician prepares a permanent replacement.

Since the 1980s, robotic machines have greatly speeded up that procedure. Sitting in the dentist’s chair takes far less time than it once did.

Michael Silveus has a dental office in northern Virginia, near Washington, DC. He describes the time saved.

“It’s about 12 minutes’ worth of chair time for the patient and the rest of the time, it’s work that’s taking place outside the patient’s mouth. “

Dr. Silveus and his assistant are preparing a patient’s tooth for a new crown. The drilling inside the patient’s mouth lasts about five minutes.

In the past, a plastic material was used to make an impression of the damaged tooth. But now, Dr. Silveus uses a video camera on a wand to inspect the tooth and the surrounding area.

Next, a computer takes over the process. It designs the new crown and creates directions for a robotic milling machine. A small cube of porcelain is placed between two drills, similar to the one the dentist uses. The porcelain is no larger than the tooth. The high-speed tools break off extra material from the cube, creating a perfectly shaped tooth crown.

To harden, the crown must be heated for about 10 minutes. During that process, its color is changed to the color of the patient’s other teeth.

Then, the dental crown is ready to be placed permanently in the patient’s mouth.

“It feels amazing. The tooth feels like my tooth.”

Many people wearing crowns will say the newer procedure is a huge improvement over older methods. But Dr. Silveus says even this technology may someday become obsolete.

“The other thing we look forward to is genetic engineering, and eventually cloning, so you can make the crown out of actually enamel, just like the patient’s natural teeth are.”

For now, Dr. Silveus says his patients are happy to be able to get a new crown in just one visit.

I’m Jonathan Evans.

VOA reporter George Putic prepared this story. Jeri Watson wrote it for VOA Learning English. George Grow was the editor.

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Words in This Story

dentist – n. a person whose job is to care for people’s teeth

dental crown – adj. and n. a covering for a damaged or implanted tooth

impression – n. something (such as a design or footprint) made by pressing or stamping a surface

wand – n. an electronic device used to gather information

mill – v. to produce (something) by grinding, crushing or cutting

obsolete – adj. no longer used because something newer exists