The effect of different surface treatments on the shear bond strength of new generation zirconia

This study aimed to assess the effect of various surface roughening techniques on the shear bond strength of three new-generation zirconia ceramics. Specimens of 4Y-TZP/5Y-TZP zirconia (IPS e.max ZirCAD), 3Y-TZP monolithic zirconia (Vita YZ HT), and 3Y-TZP/5Y-TZP zirconia (IPS e.max ZirCAD Prime) were prepared using CAD/CAM and sintered as per manufacturers' instructions. Four surface treatments—control, sandblasting, tribochemical silica coating(TSC), and Er:YAG laser etching—were applied to yield 12 subgroups (n = 10). Specimens were treated with an MDP primer and cemented using dual-cure self-adhesive resin cement. Shear bond strength was measured using a universal testing machine at 1 mm/min. Statistical analysis included Shapiro-Wilk, two-way analysis of variance (ANOVA), and Tukey HSD tests (p < 0.05). Sandblasting and TSC significantly improved shear bond strength (p <.001). The Vita YZ HT group exhibited higher bond strength compared with IPS e.max ZirCAD (p = 0.004). Cohesive and mixed fractures predominated in sandblasting and TSC groups, whereas Er:YAG laser treatment yielded bond strength similar to controls (p =.386). Shear bond strength is influenced by the type of zirconia ceramic, surface treatment, and their interaction (p <.001). Sandblasting and TSC are highly effective, underscoring the clinical importance of surface preparation for durable zirconia bonding.