Typically CAD/CAM dental restorations are milled from solid blocks of ceramic or composite resin that closely match the basic shape of the restored tooth. After decayed or broken areas of the tooth are corrected by the dentist, an image (scan) is taken of the prepared tooth and the surrounding teeth. This image, called a digital impression, drws the data into a computer. Proprietary software then creates a replacement part for the missing areas of the tooth, creating a virtual restoration. This is called reverse engineering. The software sends this virtual data to a milling machine where the replacement part is carved out of a solid block of ceramic or composite resin. Stains and glazes are fired to the surfaces of the milled ceramic crown or bridge to correct the otherwise monochromatic appearance of the restoration. The restoration is then adjusted in the patient’s mouth and cemented or bonded in place.