CAD/CAM is the latest technology that dentistry has achieved for porcelain crowns and bridges. The most important distinction from conventional metal-supported crowns and bridges is the milling of monolithic zirconia instead of using a metal framework. In some cases, aluminium oxide or zirconium oxide is used beneath the porcelain. It enables design and modelling to be carried out flawlessly, entirely on computers and by robotic equipment, without manual intervention.
The greatest advantages of aluminium oxide or zirconium oxide used instead of metal as a framework are their aesthetic appearance and durability. Unlike metal frameworks made from chromium-nickel alloys, gold alloys or titanium, these materials transmit light and perfectly reproduce tooth colour and translucency compared with older conventional porcelain crowns. Today, single-piece monolithic zirconia restorations requiring no porcelain layer are preferred. Their advantages include an absence of colour change over time and, most importantly, an absence of porcelain fracture. Because the thickness of a metal framework is unnecessary, less tissue is removed during tooth preparation and the tooth suffers less damage.
Uses:
Full-mouth rehabilitation for aesthetic or functional purposes.
Full crowns for a severely damaged individual tooth.
Bridges replacing one or two missing teeth.
Porcelain veneers bonded to the front surface of a tooth for aesthetic purposes.
Implant-supported porcelain restorations.
Procedure:
Unlike conventional tooth reduction methods for crowns, less tissue is removed and the tooth is prepared with a defined finish line. As a result, although the margin is above the gum, the grey discolouration associated with metal-supported crowns does not develop over time.
Next, an impression is taken with precise impression materials and sent to the laboratory. It is scanned with a dedicated laser device, and the data are sent to robotic milling equipment. The tooth is shaped from a block with a milling cutter, without manual shaping. Production is thus completed with zero errors.