Dental CAD/CAM is the use of computer design and computer-controlled machines to make crowns, bridges and other dental restorations. CAD means computer-aided design, and CAM means computer-aided manufacturing. A crown is a cap that covers a damaged tooth. A bridge replaces a missing tooth by joining a false tooth to the teeth on either side of the gap.
It is used in two places. In a dental laboratory, a technician designs and makes crowns for many clinics. In chairside CAD/CAM, the dentist has the scanner, the software and a small milling machine or printer in the clinic, and can make the crown during the patient's visit.
The work has four steps. First, the dentist shapes the damaged tooth and scans it with an intraoral scanner, the same kind of wand used for clear aligners. Second, the CAD software proposes a crown. It starts from a library of natural tooth shapes, and fits one to the shaped tooth, the teeth beside it and the tooth that bites against it. The dentist adjusts the shape on screen. Third, the CAM software converts the design into tool paths, the exact route that each cutting tool must follow. A milling machine carves the crown from a small block of ceramic, such as zirconia, using diamond tools cooled by water. Some clinics print the crown on a 3D printer instead. Fourth, the crown is heated in a small furnace to harden it and give it a glaze. Then it is fixed onto the tooth.
For instance, a dentist in Bhubaneswar sees a patient with a cracked back tooth. The scan takes 2 minutes, and the design about 10 minutes. The milling machine carves the crown in about 18 minutes, and the furnace takes about 20 minutes more. The crown is fixed the same morning, about two hours after the patient arrived. The visit and the bill are recorded in the clinic's practice management software.
Without CAD/CAM, the dentist takes an impression and sends it to a laboratory. The patient wears a temporary crown, and comes back after one or two weeks to have the real one fitted. Chairside CAD/CAM saves that second visit. But the machines are expensive. So in India, most dentists still send their work to dental laboratories, and many of those laboratories now use CAD/CAM themselves.
Both ways are examples of mass customisation, in which every product is made to one person's shape.