CEREC® systems may be described as measurement devices that operate according to the basic principles of confocal microscopy (3, 4) and according to the active triangulation technique (3, 5 and 6). The latest version of the milling centre, CEREC inLab® MC XL (see Figure 3), is capable of milling a crown in as little as 4 minutes. The latest versions of the CEREC® system (see Figure 1 and 2) are capable of producing inlays, onlays, crowns, laminate veneers, and even bridges and combine a 3D digital scanner with a milling unit (view Figure 3) to create in-office dental restorations from commercially available blocks of ceramic or composite material in a single appointment (1). CEREC® (an acronym for Chairside Economical Restoration of Esthetic Ceramics) was introduced by Sirona Dental System GMBH (DE) in 1987, and it has undergone a series of technological improvements, culminating in the CEREC AC® powered by BlueCam®, launched in January 2009. The aim of the present publication is the evaluation of all these existing devices with particular attention to the working principles they are based on, their features and performances. Furthermore, data about the accuracy of the available instruments is missing. Moreover, the 3D virtual model is often reconstructed by post-processing single images (acquired from a single perspective) accordingly the reconstruction is not performed in real time with a continuous data capture. For example it is often necessary to apply some coatings on the teeth to minimize the noise of the measurement and to rest the camera wand on a tooth to get a steady focus.
As already mentioned, even if a lot of advantages in taking digital impressions are attainable, there subsist also some disadvantages related to the existing devices.
some of these are already commercially available.
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