Preparation of Zirconia Plus
Zirconia Plus constructions are produced from solid zirconia blocks. The core thickness shall not be less than 0.4 mm. For bridges and molars, we recommend that the core thickness is no less than 0.5 mm. We recommend that the core is porcelain covered.
Dimensions of the preparation
Maximum size of the Zirconia Plus block is 45x16x16 mm, which is what the construction must fit within. Note that it usually will be an aesthetic layer porcelain buccal that can build 1-2 mm and buccal/lingulat/proximal may be 1-1.5 mm.
Round off sharp edges and corners
As with all prosthetics one achieves a better result if one rounds the sharp edges and corners. This is true for traditional casting techniques and are at least as important in CAD/CAM production.
Parallel preparations on bridge constructions
It is important that the preparations are parallel in bridge constructions. This applies to both cast as CAD/CAM-derived products. With a design program, however this is visually clearer.
It usually achieves a higher aesthetic level if the preparation is done with some sort of shoulder. With a chamfer the dental technician get space for porcelain.
The minimum recommended link dimension is 3×4 mm and bridge span should not exceed 15 mm. For longer span the links height should be carefully considered.