It’s understandable why dentists would offer “crowns in a day.” After all, everyone in our society is used to getting things now, and the ability to promise the convenience of getting a

dental crown made today, without the need for a temporary crown or a second visit to fit the crown onto the tooth.

But at Rice Dentistry, we are dedicated to ensuring the best quality for our patients, and that’s why we don’t offer this style of crowns, and won’t, as long as research shows that the fit isn’t as good as dental crowns made using conventional approaches. It’s better to wear a temporary crown for a couple of weeks than pay for a permanent crown but only get a temporary one.

The CAD/CAM Technology

The technology behind same-day crowns is computer-aided design/computer-aided manufacture (CAD/CAM). In this technology, a digital image is taken of your tooth using a 3D scanner. This digital image is then used to plan the crown in the computer. The shape of the crown is then sent to a computer-controlled milling machine, which uses a diamond-tipped mill to carve the dental crown out of the source block.

Testing CAD/CAM Crowns

closeup for dental onlay on a molar tooth shown on a plaster modelThere are two major components of the CAD/CAM process that can go wrong, leading to poor fit: inaccurate scans and inaccurate milling.

To test the impact of these two error on the fit of CAD/CAM crowns, researchers created 30 crowns using a pressed-ceramic system (the most common process used in dental labs) from a physical impression in polyvinyl siloxane (PVS), 30 crowns made using a CAM system from a PVS impression, 30 crowns made using a pressed ceramic system from a digital impression, and 30 crowns made using a full CAD/CAM process. They found that the crowns made using a physical impression from pressed ceramic–the traditional crown system–gave the best fit.

Although the difference was only about 1/25th of millimeter (1/625th of an inch), it was a statistically significant difference.

Aesthetics Matter, Too

In addition to the issue of fit, we have also found that the appearance of dental crowns from this system doesn’t match what we get from our labs. Since we want our patients to be happy with the fit and appearance of their crowns, we’re not going to offer crowns in a day, yet.

But we’ll keep looking at the technology, and will be happy to consider it again when it finally meets our standards.

If you are looking for the highest quality dentistry in Orange County, please call (949) 551-5902 for an appointment at Rice Dentistry in Irvine.