Fracture Resistance, Surface Roughness, and Microtensile Bond Strength of Monolithic Zirconia to Resin Cements after Plasma Treatment.

Objectives: This study aimed to assess the effect of surface treatment with plasma on surface roughness (SR) and fracture resistance (FR) of monolithic zirconia, and its microtensile bond strength (MTBS) to resin cements. Materials and Methods: This in vitro, experimental study was conducted on 40 monolithic zirconia crowns for FR test, 100 zirconia rods for MTBS test, and 40 zirconia blocks for profilometry. According to the surface treatment type, the samples were randomly assigned to 4 groups of (I) control (no surface treatment), (II) argon-oxygen plasma (AOP), (III) argon plasma (AP), and (IV) sandblasting (SB). FR of crowns and MTBS of zirconia rods to Allcem Dual and Panavia SA resin cements were measured by a universal testing machine, surface texture was evaluated by atomic force microscopy (AFM), and SR was measured by a profilometer. Data were analyzed by one-way and two-way ANOVA, Tukey's test, and independent t-test (alpha=0.05). Results: There was a significant difference in SR among the groups (P=0.003). The AP group had significantly lower SR than other groups (P=0.01). FR was not significantly different among the four groups. The MTBS in the SB and AOP groups was significantly higher than that in the control and AP groups for both resin cements. MTBS was not significantly different between the two resin cements within each group. Conclusion: None of the surface treatments affected the FR of zirconia crowns. AOP and sandblasting techniques increased the MTBS of zirconia to resin cements with unnoticeable change in SR.