Evaluation of Different Zirconia Surface Treatments on their Microhardness

Abstract

Aims: To investigate the effect of mechanical and chemical surface treatments including (AL 2 O 3-110µm) and citric acid solution (30%) on the microhardness of zirconia ceramic. Materials and Methods: Twenty four cubic shaped specimens were prepared from partial sintering zirconia (IPS e.max ZirCAD MT).Specimens were randomly assigned into three main groups (GI, GII, and GIII) according to the surface treatment methods (n=8). Group I: zirconia surface left without surface treatment (control), Group II: In this group all specimens were subjected to sandblasting with 110 µm Aluminum oxide particles (Al2O3), while Group III: The surface was treated with citric acid solution 30% for 10 minutes. Force of Vickers microhardness was applied on the intaglio surface of the zirconia specimen at 0.5 kg for 30 seconds. Data were analyzed with one way ANOVA at 5% level of significance. Results: Sandblasting with AL2O3 110µm significantly increased the Vickers microhardness value of the zirconia surface. Chemical treatment with 30% citric acid did not exhibit any significant changes in comparison to the control group. Conclusions: Within the limitation of this in vitro study, the mechanical surface treatment of the zirconia surface with AL2O3 improves the surface microhardness.

Effect of Simultaneous Sintering of Bioglass to a Zirconia Core on Properties and Bond Strength

“…The Z-Prime group had an insignificantly lower hardness value than the sintered group, which might be attributed to the chemistry of the carboxylic monomers that contained conventional MDP. The sandblasted group had a significantly higher hardness value than all other groups; this might be attributed to the precipitation of Al 2 O 3 particles within the abraded surface, as confirmed by the EDS chemical analysis results ( Table 2 ), or could be due to the stress-induced transformation from the tetragonal to the monoclinic crystal phase, accompanied by an increase of the strength property [ 17 , 18 ].…”

“…In our study, a silica–calcium-rich layer with an average particle size of 0.224 μm was formed on the zirconia substrate as a glass surface layer. The bioglass surface layer was homogenous, even, and intact, with no cracks or defects [ 17 ].…”