Effect of surface treatments on the properties and morphological change of dental zirconia

Abstract Statement of problem Creating a rough surface for bonding with airborne-particle abrasion with alumina may damage the surface of zirconia. Other treatment methods for creating a bonding surface without causing damage require investigation. Purpose The purpose of this in vitro study was to find ways of treating the zirconia surface without causing flaws, debris, pits, microcracks, or tetragonal to monoclinic phase transformation. Material and methods Yttria-stabilized tetragonal zirconia polycrystal ( Y-TZP) ceramic surfaces were treated with gas plasma, argon-ion bombardment, 150-μm abrasive zirconia particles, and abrasive 150-μm alumina particles; untreated surfaces were used as the control group. X-ray diffraction (XRD) and confocal Raman spectroscopy were used to study the phase transformation. The roughness of specimens was measured with a confocal 3D laser scanning microscope. Modification of surface topography was analyzed with field emission scanning electron microscopy (FESEM), and the flexural strength was measured with a universal testing machine. Statistical analyses were performed with 1-way ANOVA, followed by comparison of means with the Tukey honest significant difference test. The standard deviation was calculated with descriptive statistics. Results The sintered Y-TZP ceramic used in this study showed 2 phases, tetragonal and cubic. Specimens abraded with 150-μm alumina particles showed a higher monoclinic volume fraction (V mXRD =8.68%) and roughness (R a =0.91μm) than specimens abraded with 150-μm zirconia particles (V mXRD =1.22%, R a =0.08μm). One-way ANOVA indicated a significance difference in roughness among groups ( P P >.2). FESEM measurements showed that airborne-particle abrading Y-TZP surfaces with 150-μm alumina particles caused more damage to this area than the other methods. Conclusions Y-TZP ceramic surfaces treated with zirconia particles, argon-ion bombardment, and gas plasma were damaged less in comparison with surfaces abraded with alumina particles.