Various impact of polishing system on roughness, microhardness, phase transformation, flexural strength of monolithic zirconia

Abstract

Objective: The aim of this study was to evaluate the effect of different surface polishing systems and autoclave aging process on the surface properties, phase transformation and flexural strength of monolithic zirconia. Methods: Forty eight Ø15×1.2 ±0.01-mm disks of one monolithic zirconia materials (Prettau, Zirkonzahn) were prepared glazed, and assigned to 3 groups: A control group with no additional treatment after glaze; and 2 groups in which the glaze layer was removed and the surfaces polished using 2 different polishing systems (OptraFine and Meisinger). After the polishing, each group was divided into two and one of these was aged in an autoclave. The surface roughness of the samples was analyzed using a profilometer device, the surface microhardness was evaluated using the Vickers microhardness test. Both atomic force microscopy and scanning electron microscopy were used to image the surface properties. Phase transformation was analyzed using X-ray diffraction. Finally, the flexural strengths were evaluated. Results: The effects of surface polishing applied on monolithic zirconia specimens were found to be statistically significant. The effect of autoclave aging on the phase transformation was significant, but the effect on surface roughness, microhardness, and flexural strength was not statistically significant. Conclusion: It was determined that the surface polishing systems applied to the monolithic zirconia specimens affected the surface properties, phase transformation, and flexural strength. The autoclave aging process did not affect the surface properties and flexural strength but affected the phase transformation.