digital dentistry _ NobelProcera I Fig. 2a Fig. 2b Fig. 2c Fig. 3a Fig. 3b Fig. 3c ment for all glass-based ceramics—is only applicable in clinical situations with reduced vertical crown height or extensive preparation taper in which loosening of a restoration is likely (Figs. 1–5). Clinical simplicity is relevant not only to restoring natural teeth, but also to placing dental implants. It is important to realise that CAD/CAM-manufactured implant superstructures do not require any change in clinical protocol when compared to conventional cast restorations. Rather, the consistent fit of milled components reduces the need for chairside adjustments significantly. _Safety for the patient Providing the patient with a reliable and longterm successful restoration is key in today’s highly competitive dental market. Product and material quality significantly influence the long-term clinical outcome. From a clinical perspective, important aspects to consider include long-term stability in the oral cavity, bio-compatibility, post-processing options (for example, type of veneering material), reasonably low costs and clinical versatility. While the aesthetic potential was initially due to using high-strength all-ceramic restorations, the true benefit of Y-TZP/ZrO2 (yttria-stabilised polycrystalline tetragonal zirconia), for example, is its excellent bio-compatibility paired with flexural strength values that allow for application in any area of the oral cavity for both natural teeth and dental implants. When in close contact with the surrounding tissues, the reduced plaque and bacterial accumulation, as well as the development of currently undefined pseudo-attachments leads to long-term tissue stability around these components (Figs. 6 & 7). This fact makes zirconia products the primary choice not only for non-compromised clinical situations, but also for pre-existing periodontal conditions whenever restorations, such as implant abutments, are in close contact with surrounding tissues. Despite these advantages, it is important to understand and respect the material properties of these materials. If inadequate space or extensive leverage arms are unavoidable, alternative materials should be selected. Advanced systems such as the NobelProcera system (Nobel Biocare) offer Figs. 2 & 3_Efficient CAD/CAM systems support the dental technician (NobelProcera System software, Nobel Biocare) by providing automated tools for anatomic framework design (Figs. 2a–c) and in manufacturing the ready-to-use components to eliminate any alterations after sintering (Figs. 3a–c). Fig. 4_Shaded zirconia (NobelProcera Bridge Shaded Zirconia, Nobel Biocare) guarantees maximum strength combined with excellent aesthetic results and application of any veneering material within the CET range of zirconia. Fig. 4a Fig. 4b cosmetic dentistry 4 _ 2009 I 41