Silica Deposition on Zirconia Via Room-Temperature Atomic Layer Deposition and Bond Strength to Resin Cement

Objective: This study aimed to evaluate the effect of the controlled growth of yttria-stabilized zirconia (Y-PSZ) transformed layer and silica deposition via Room-Temperature Atomic Layer Deposition (RT-ALD) on bond strength between Y-PSZ and resin cement.Material and Methods: Y-PSZ specimens (IPS e.max ZirCAD, Ivoclar Vivadent) with different translucencies (MO, MT, LT) were exposed to surface treatments (n=10): control (C - no treatment), aged (A - 15 h, 134°C, 2 bar in autoclave), blasted (B - 50 μm Al 2 O 3 ), silica deposition via Rt-ALD (R - 40 cycles of sequential exposure to tetramethoxysilane orthosilicate and ammonium hydroxide vapors) and aged followed by silica deposition (AR). Specimens were bonded to resin composite cylinders with a resin cement (Multilink Automix) and shear bond strength (SBS) test was performed. Failure mode and surface chemical and topographical characterization (energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy) were performed. SBS data was analyzed by two-way ANOVA and Tukey test (α=.05).Results: The results of the two-way ANOVA indicated that surface treatment (p<.001) and the zirconia translucency/surface treatment interaction (p=.001) had a significant effect on SBS. Silica deposition resulted in bond strength values similar to alumina blasting (p>.848), with no significant effect of aging (p>.664). Higher incidence of composite resin cohesive failures was observed in the R-treated specimens (MT, LT), with and without aging. SEM images showed a rougher surface for B-treated specimens, while no changes were observed for the other treatments. XPS analysis showed a nanofilm of silica deposited over the zirconia surface after silica deposition.Conclusion: RT-ALD was an effective technique to deposit silica on the surface of zirconia, generating bond strength results similar to alumina-blasted specimens