Coated dental articles and related methods of manufacture

A coated dental article comprising:

• dental article having an outer surface;
• and
• a coating extending across at least a portion of the outer surface, the coating comprising a zirconia alloy, the zirconia alloy comprising an alloying compound selected from the group consisting of yttrium oxide, calcium oxide, cerium oxide, magnesium oxide, and combinations thereof,
• wherein the coating displays a Δa* value greater than 0.5 relative to an uncoated article for a white reflectance standard background before heat-treatment and a Δa* value of 0.5 or less relative to an uncoated article for a white reflectance standard background after heat treatment and a 60 degree gloss value exceeding 150 percent that of the uncoated article, and
• wherein the coating exhibits enhanced abrasion resistance as evidenced by a lack of chipping after 16000 cycles of the Abrasion Resistance Test
• wherein the dental article is an orthodontic bracket having an archwire slot, and wherein the coating is deposited on a least a portion of the archwire slot.

A method of making a coated dental article, the method comprising:

• providing a dental article having an outer surface;
• and
• depositing on at least a portion of the outer surface a coating comprising zirconia that is at least partially stabilized by an alloying compound selected from the group consisting of yttrium oxide, calcium oxide, cerium oxide, magnesium oxide and combinations thereof, wherein depositing the coating takes place at a pressure of 10 millitorr or less, wherein the deposited coating has a layer thickness ranging from 25 to 1000 nanometers;
• and
• subsequent to the depositing step, heat-treating the coating in an oxygenated environment at a temperature ranging from 300 to 700 degrees Celsius, such that the coating displays Δa* value greater than 0.5 relative to an uncoated article for a white reflectance standard background before heat-treatment and the heat-treated coating displays a Δa* value of 0.5 or less relative to an uncoated article for a white reflectance standard background, and wherein the heat-treated coating is translucent.