Effects of the organic additives on dental zirconia ceramics: structural and mechanical properties

Zirconia ceramics have gained lot of interest as restorative materials because of remarkable mechanical properties; such as high strength and toughness, good biocompatibility, and aesthetic properties. But the problem with zirconia is inertness with the body fluid and it resists the formation of bonds with bones and tissues. This problem can be minimized by using some biocompatible additives. This explorative study was performed to examine a possible impact of organic additives’ ratio on ZrO2 thin films. Glucose, fructose and water were added into pre-synthesized zirconia with variation in ratio from 1:1:5 to 1:1:25. Formation of pure tetragonal phase was investigated at glucose: fructose: water ratio of 1:1:10 by X-ray diffractometer. As the water content increases adsorption of OH ions produces tensile stresses which lead to transformation of pure tetragonal phase to monoclinic phase. The mechanical properties of the samples were characterized by Micro Vickers hardness tester and hardness of the samples is in the range of 565–1,053 HV. High value of hardness and low value of porosity has been observed in thin film with glucose: fructose: water ratio of 1:1:10. Surface morphology of thin films is observed by scanning electron microscope. Fourier transform infrared spectroscopy study presents the formation of tetragonal zirconia bond with presence of OH ion. Relatively weak bond of C–H bonding was formed; indicating the presence of organic additives in ZrO2. High temperature tetragonal phase has been obtained in as-deposited thin film using water-soluble and body fluid compatible organic additives without any heat treatment. Hence, these as-deposited thin films, with pH 5.5, have potential application as protective coatings on teeth.