Fusion Sputtering for Bonding to Zirconia-based Materials

Purpose: To evaluate the influence of fusion sputtering on zirconia-resin microtensile bond strength after 6 months of water storage. Materials and Methods: Zirconia disks received one of the following surface treatments: particle abrasion with 50-µm aluminum oxide particles or fusion sputtering, while as-sintered specimens served as a control. The prepared zirconia disks (Lava Zirconia) were bonded to pre-aged composite disks (Filtek Z250) using a phosphatemonomer- containing resin cement (RelyX Unicem), and the bonded specimens were sectioned into micro-bars (1 x 1 x 6 mm) which were either immediately tested or after 6 months of water storage (n = 25). Scanning electron microscopy (SEM) and surface roughness were performed for the prepared specimens. Data were analyzed using two-way ANOVA (α = 0.05). Results: Particle abrasion (33.1 MPa) and fusion sputtering (42.5 MPa) produced significantly higher MTBS values and resisted degradation after 6 months of water storage, while as-sintered specimens (12.4 MPa) demonstrated a significant reduction in bond strength after water storage (2.9 MPa). SEM examination indicated that fusion sputtering resulted in the creation of retentive zirconia beads on the treated surface, which enhanced micromechanical retention with adhesive resin and prevented interfacial failure. Conclusions: Fusion sputtering is a new and a simple method suitable for enhancing the bond strength of adhesive resins to zirconia-based frameworks. Keywords: fusion sputtering, MTBS, zirconia, SEM