Because of the developments in the field of all-ceramic materials, which have quite different material properties compared with traditional materials for prosthetic treatment, it was also important to adapt the preparation to the new circumstances. Practiced design guidelines for the restorative treatment of teeth for allceramic restoration are illustrated in this article. Based on traditional retentive preparation shapes, modifications of these geometries "designed for ceramics" were developed and postulated. Despite excellent 15-year long-term results, it is important to draw the appropriate conclusions from failures that have occurred. The geometry of the cavities for all-ceramic inlays must be matched much more to the material-specific properties of hard and brittle restoration materials. Cavities designed for ceramics must therefore have the simplest possible basic geometry. Because of adhesive bonding, a retentive shape of the preparation is not necessary. Previous ceramic inlay designs must be redefined to achieve an increase in the fracture resistance of the ceramic. Keywords: CAD/CAM technology, strength characteristics, preparation backgrounds, hard core materials, static load test, all-ceramic restoration