Cementation of Full-Contour Zirconia Restorations
The clinical procedures for cementation of zirconia restorations are similar to those used when cementing gold crowns. The primary resistance and retention form of the preparation is mainly responsible for the long-term success of the restoration. Because zirconia cementation uses a traditional cementation procedure, there are many material options.
Glass ionomer and resin modified glass ionomer cements are the most commonly used. My recommendation is to follow the recommended protocols for the brand you currently use.
When considering possible bonding of zirconia restorations to the tooth, realize that the conventional methods applied to the bonding of silica-based ceramics are not successful. You cannot acid etch and silanate the intaglio surface as you can with lithium disilicate (e.max) or other glass ceramic restorations.
Recently, new products have been developed that increase the bond of resin cements to zirconia. Data from outcome studies have confirmed that a combination of airborne particle abrasion (50 micron Al2O3 at 2.5 bar) and resin composites containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) monomer, achieve a durable bond of zirconia to a prepared tooth. For example, the 3M Scotchbond Universal Adhesive contains the MDP monomer, which optimizes its self-etch performance when used in combination with Relyx Ultimate adhesive resin cement.
The bottom line is that cementation of zirconia restorations is highly successful when there is adequate resistance and retention form. With current advancements of dental adhesives, it is now possible to increase the retention of the restoration of the bonding process with the appropriate materials.