In dentistry, inlays and onlays are a form of indirect restoration. This means they are made outside of the mouth as a single, solid piece, that fits the specific size and shape of the cavity. The restoration is then cemented in place in the mouth.
The CEREC system is a CAD-CAM device. It allows for inlays and onlays to be created and fitted all within one appointment, no impression taking is needed due to the 3D scanning of the machine.