Machinable dental restoration

The second type of DICOR glass-ceramic was developed for the purpose of machining dental restorations. This glass-ceramic carries the brand name DICOR MGC. The material is machined using the Cerec 1 system (Siemens AG, Germany). Details of this machining system have been reported by Mormann et al. (1987). 

In comparison to the IPS Empress microstructure, a different type of leucite glass-ceramic was developed by Schweiger et al. (1999). The leucite-reinforced glass-ceramic was developed as a biomaterial for dental restoration. The material can easily be machined by a CAD/CAM system. The mechanical properties are characterized by a flexural strength of 135-160 MPa and a fracture toughness as of 1.3 MPa m (section ProCAD in Section 4.4.2 dental glass-ceramics). 

Two types of DICOR glass-ceramics are produced for dental applications. The first type is a castable glass-ceramic with which dental restorations are fabricated in the dental laboratory. The second type is a machinable glass-ceramic with which dental restorations are machined using CAD/CAM technology in the dental clinic. 

The ProCAD (professional computer assisted design) system is directed to the preparation of dental restoration by machinability using the CEREC 2 or CEREC 3 apparatus. The ProCAD system comprises ProCAD glass-ceramic blocks shade/stains kit the furnaces of Programat type, e.g., PI00 or Programat XI (Ivoclar Vivadent AG) and a Cem kit. 

The processing of the glass-ceramic dental products is carried out by machines of the CEREC 2 or CEREC 3 system. The CEREC system is a CAD process reported by Mormann and Krejci (1992) and Pfeiffer (1996). This system allows the dentist to prepare a dental restoration within approximately 15 minutes. Thus a chair-side preparation of a dental restoration is possible. The CAD processing of ProCAD dental restorations using the CEREC 3 system is reported by Mormann and Bindl (2000). 

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