CEREC or E4D ceramic crowns, inlays and onlays

What is CEREC or E4D technology?

Historical background

The CEREC technology was the first of this type to be available on the market. The meaning of CEREC has evolved throughout the years, from “CEramic REConstruction” to “Chairside Economical Restoration of Esthetic Ceramics”. The E4D has appeared more recently in the dentists’ offices. While it comes from a different company, it is very similar to the CEREC technology. Both methods provide patients with the same high-quality ceramic restoration done in one appointment.

This type of restoration is relatively new because it has only been used on patients for the first time in 1985. Since then, the number of dentists using it is on the rise. It has become essential for many dentists to master this technology because patients are increasingly requesting it. According to the latest statistics (2013), about 38,000 dentists use CEREC or E4D technology worldwide and almost 7 million restorations are performed each year, for a total of 28 million restorations carried out since this technology is available. These figures are expected to climb because this technology is still growing. Indeed, new applications are developed and material upgrades are continuously done.

The basic principle behind the CEREC or E4D technology

The CEREC or E4D technology allows creating inlays and onlays (partial crowns) or full crowns in one appointment. It is a computer-aided design and computer-aided manufacturing (CAD/CAM) dental system.

The resulting restoration can replace a full or partial natural tooth crown that is not functional anymore. It is also used to substitute a faulty or damaged filling.

Equipment used and treatment steps

CEREC or E4D technology allows the dentist to design, produce and install custom-made ceramic (porcelain) restorations in a single appointment. In order to do this, the dentist uses:

• A camera that takes digital images of the problematic tooth, adjacent teeth, antagonistic teeth (located on the opposing arch) and occlusion (contact between teeth);
• A design software that uses the images from the camera to model the crown or inlay;
• A computerized robot that produces the crown or inlay by milling the actual restoration from a solid block of material using diamond burs. A delay ranging from 5 to 20 minutes is usually required for this step. The crown or inlay is then ready to be bonded to the tooth using a high-performance resin cement. In fact, a thin film of adhesive cement is used and the strength of the resulting joint is superior to formerly used adhesives.

The first generations of CEREC technologies were using bidimensional (2D) models. Since the beginning of the 2000s, a 3D model is produced by the design software. The crown or inlay produced with CEREC or E4D technology can be created by the computerized robot that reads 3D models.

It is worth noting that some dentists that offer CEREC or E4D restorations do not have, for some reason, the milling unit that makes the artificial crown or inlay on the spot. The dentist chooses to send the digital images to an external dental laboratory which will be in charge of the fabrication. In this case, the patient may not receive a crown or inlay in one appointment because of the processing and delivery time. However, the patient will still benefit from a very high-quality restoration.