The restoration is etched so it will bond, then a special type of glue is applied and cured briefly with a light. Within minutes, Nielsen's tooth looks as if it never needed any work at all.

Many people have never heard of CEREC, though it's nearly 20 years old. It debuted in Europe and has undergone some changes from the original technology. It arrived in the United States more than a decade ago and has slowly caught on, aided now by a simpler 3-D version that was introduced about a year ago.

Still, only an estimated 2-3 percent of Utah dentists have the technology, distributed solely in this country by Patterson Dental, because the technology costs around $95,000.

Larsen says there are many advantages, but it's not for every tooth. Although CEREC provides a new option for some teeth, dentists have to be selective. Some teeth still require a conventional crown.

Myles Preble, a dentist in Salt Lake City, has used CEREC for almost five years.

"The technology is much more user-friendly now. The new 3-D version (CEREC 3-D) is so much nicer. You can mill in more of the anatomy instead of having to cut it in."

But even with the earlier CEREC models, he says, he has had no breakage. That's a tribute to the material, he notes. It's more dense.

The goal with CEREC is never to go below the gum line, Preble says, and that makes it "look like it grew there."

As many as four teeth can be done comfortably at a time, he says. And although the American Dental Association still also backs use of silver amalgam fillings, he prefers CEREC. "To me, there is no comparison. It's absolutely great. It's the best restoration technology can provide and the most toothlike. It should be there a long time."

Nelson Glassett, a dentist in Salt Lake County, says about half his patients choose a crown and half choose CEREC. It's an option that insurance covers as it would a crown. Glassett has used it for both crowns and inlays and likes the fact that he knows right away how it's going to fit. "With CEREC, we can take a picture of the bite, the opposing arch, we can make it go up and down and see where it's hitting."

He doesn't underestimate the benefits of getting the job done in a single visit, either. When a crown comes back from the lab, if it doesn't fit he has to make a new impression and send it back, adding another couple of weeks to the process. With CEREC, if he has one that didn't mill perfectly, he makes an adjustment, fixes it and fits it right then. But that's a rare occurrence.

"That's one of the biggest points. The time for the patient. The other thing is the materials used to mill the crowns or onlays or inlays are out of material that's extremely compatible with natural enamel, so it won't cause more wear to the opposing teeth. For people with a porcelain crown, it's so strong it wears away enamel over time."