Are One-Day Crowns Worth the No Wait?
- By LAURA JOHANNES
The Ache: Getting a crown for a weak or damaged tooth can be a big pain—and not just in the tooth. The process usually requires at least two dentist visits and a one-to-three-week wait for the crown to be made. The E4D system includes machines for digital impressions and milling.
The Claim: Dentists say, with digital technology, they can make a crown in the office while a patient waits. The process takes only an hour or two.
The Verdict: One-day crown technology is convenient and produces durable ceramic crowns, dentists say. But there are “aesthetic limitations” to the one-day crown procedure making it a less appealing option for front teeth, says Jacinthe M. Paquette, a Newport Beach, Calif., prosthodontist.
A crown is a cap made to cover a damaged tooth. To prepare for the crown, dentists drill to remove the decayed portion and shape the tooth for the crown. Depending on the dentist and location, a traditional crown can cost $800 to $2,000 or more, and take at least two visits and a wait in between while a lab makes the crown.
The one-day crown systems are sold bySirona Dental Systems Inc.SIRO -1.83% of Long Island City, N.Y., and D4D Technologies LLC of Richardson, Texas, which does business as E4D Technologies. The machines are now available in about 10% to 15% of U.S. dentists’ offices, the companies say.
The systems, which cost dentists about $100,000 to $130,000, include a computer that takes digital images of the damaged tooth, software to design the crown and a milling machine, the companies say.
Dentists say they don’t charge more for a one-day crown than a traditional crown partly because the machine saves on lab costs. D4D and Sirona both say their crowns are generally covered by dental insurance that covers traditional crowns.
The process starts with the dentist using a wand with a camera on the end that uses reflected light to create a three-dimensional picture of the tooth and adjacent teeth. The software suggests a design for the crown, which the dentist can tweak. A mouse click sends the design to the milling machine, which sculpts the tooth from a small block of ceramic.
Several studies show restorations made using the computer-assisted systems fit well and have good longevity, but more research is needed, particularly comparing lab-made crowns to those made in dentists’ offices, scientists say.
And if cosmetic appearance is paramount—particularly on the front teeth—a patient may prefer going the traditional route because “the artistry is just a little better,” says Steven D. Spitz, a Brookline, Mass., dentist who bought an E4D machine in 2011.
Teeth aren’t a single color, dentists say, but yellowish at the gumline with gradually changing color until they become nearly translucent. In the one-day process, dentists can simulate this effect by painting on colors with tiny brushes.
But in the lab, a technician called a ceramist can achieve an even better result by layering different colors of ceramic.
Lab-made crowns may be better for people who clench their teeth, dentists say. Clenching puts a patient at higher risk of breakage, they say, so they might prefer a gold crown—the strongest kind—which can’t currently be made with the small mills in dentists’ offices.