Esthetics in and with All-ceramic Restorations

All-ceramic dental restorations get an impact in prosthodontic therapy concepts due to their esthetic advantage and their excellent biocompatibility - which are the main prerequisites to meet the demands of patients nowadays. However, glass ceramic needs an adhesive cementation to reinforce its weak strength. The limited indication to veeners, inlays, onlays and anterior single crowns caused a long-term success proven by several clinical trials. An "add on" of these indications are now possible by using frames of high tech ceramic zirkonia. The so called "ceramic steel" can be used for three or more unit fixed partial dentures (FPD's) even in the posterior regions. Additionally the high strength and fracture resistance of zirconia provides a thin thickness of crown- and bridge frameworks causing a minimal invasive shape of a tooth preparation. Even ceramic implant abutments and conical taper crowns show an increased survival rate compared to other all ceramic systems. Unfortunately zirkonia can be only processed by a CAD/CAM based milling machine. To prevent grinding the very strong zirkonia bulk, the pre- or semi-sintered zirkonia, is milled in a 30% enlarged three dimensional form to compensate the shrinkage in the post process of sintering. This procedure saves costs and will offer the replacement of standard porcelain fused to metal restorations by all ceramic single crowns and FPD's in the near future. Keywords: dental, all-ceramic, CAD/CAM, fixed partial denture, FPD, fused to metal restorations, PFM, esthetic, aesthetic, biocompatible, zirconia, Semi sintered, hot isostatic pressed, embriddlement, flexural strength