Analysis of the Surface Condition and Changes in Crystallographic Structure of Zirconium Oxide Affected by Mechanical Processing.

Zirconium oxide is a material commonly used in dental prosthetics for making cups of permanent prosthetic restorations. In order to properly prepare the surface of zirconium oxide for prosthetic treatment, it must be veneered with ceramics. The quality of cup-veneered ceramics is dependent on many factors, including the surface free energy (SFE) and transformation of zirconium oxide. The aim of the study was to investigate the type of phase transition and the value of free energy of the surface subjected to machining (wet and dry grinding, polishing). Quantitative and qualitative phase identification measurements showed that mechanical treatment causes transformation of the tetragonal phase into a monoclinic phase in the zirconium oxide surface. Prepared samples were analyzed by means of X-ray diffraction (XRD), which confirmed the phenomenon of transition. Measurements of the wetting angle and the calculated values of the surface free energy (SFE) showed no significant differences between the samples subjected to each treatment.