Manufacturing advancements in zirconia have led to today's innovative offerings. Multilayer zirconia discs are unique in the fact that they are pre-shaded and offer a color gradient to produce lifelike esthetics.
Manufacturers are now able to produce zirconia discs with a natural built-in transition from dentin to incisal. This natural gradient within the disc produces results similar to simple hand-built ceramic techniques. With multilayer zirconia as the restorative material, laboratories are able to utilize CAD/CAM technology to its fullest ability.
Post-process finishing has now become very predictable and replicable when implemented correctly in the modern laboratory. The restoration is designed in full contour, then milled, and the green stage is finished by applying surface texture and characterization. While not required under most manufacturer recommendations, this is truly where the technician's artistry helps bring the true potential of the material to life.
The global acceptance of zirconia in dentistry has been a revolution. This is partly due to limited tooth preparation requirements, allowing dentists to utilize preparation techniques they have become accustomed to over many years .
After sintering, the restoration is finally adjusted and checked for accuracy on the die. Once the restoration is verified as accurate, a simple stain-and-glaze technique easily achieves individual characterization of the final restoration .
The implementation of multilayer zirconia allows for a predictable digital workflow from diagnostic wax-up to final restoration. These esthetic results were previously only possible with labor-intensive layering techniques but are now achievable in single-unit cases to full-mouth rehabilitation without the need for the ceramic application.
Multilayer zirconia is currently offered by multiple manufacturers, and new variations continue to be launched onto the market. Vsmile offers three types (STML , UTML , SHTML)of multilayer zirconia disc with different translucency and strength to meet your individual needs.
There is a new family of zirconia that is considered gradient zirconia. The yttria elements in the zirconia matrix have varying levels of concentrations within the same disc, providing the laboratory technician the opportunity to place the restoration in the best possible location while nesting for lifelike esthetics. Placing the CAD design for anterior monolithic crowns in the top side of the disc will lead to more translucent restoration with lower MPa values while placing the restoration towards the lower side of the puck will provide lower concentrations of yttria, and therefore producing a stronger (higher MPA), more opaque zirconia, appropriate for substructures and frames. These gradient zirconia varieties do not have a delineation between the different layers, but rather have a gradient or range of Y5 at the very top, transitioning to Y4 in the middle and ultimately Y3 at the bottom. With multilayer zirconia as the restorative material, laboratories are able to utilize CAD/CAM technology to its fullest ability.
