ALEXANDRIA, Va., April 7 -- United States Patent no. 12,594,223, issued on April 7, was assigned to Ivoclar Vivadent AG (Schaan, Liechtenstein).
"Gradient composition zirconia dental materials" was invented by Jorg Reinshagen (Pforzheim, Germany), Henning Meyhofer (Stuttgart, Germany) and Frank Rothbrust (Rons, Austria).
According to the abstract* released by the U.S. Patent & Trademark Office: "Provided are pre-sintered and sintered zirconia dental ceramic materials. The materials have a gradient in yttria content. The materials may have a gradient in one or more physical/mechanical property and/or one or more optical property. The materials may be made by mixing at least two zirconia ceramic powders having different yttria content. A si...