Influence of Y-TZP ceramic treatment and different resin cements on bond strength to dentin

Evaluating the bond strength (σ) of resin cement systems (RXA - RelyX ARC; RXU - RelyX U100; and PF - Panavia F) to dentin and yttria-stabilized zirconia-based ceramic (YZ - In-Ceram YZ) after different surface treatments and aging.

Occlusal dentin of 54 human molars was exposed and conditioned following manufacturers' instructions. Fifty-four YZ blocks were sintered and divided into two groups according to surface treatment: PA - airborne particle abrasion, and SC - tribochemical silica coating. All treated YZ blocks were cemented to dentin using one of the cement systems (RXA, RXU, and PF) following manufacturers' recommendations, which includes specific silane agents. Teeth-cement-ceramic blocks were stored in 37°C distilled water for 24h before cutting into non-trimming bar-shaped specimens (adhesive area, A=1±0.1mm(2)). Specimens (n≥12) were assigned to one of the following conditions: N - no storage; W - stored in 37°C distilled water for 60days; and TC - thermal cycling (5-55°C; 10,000 cycles). All specimens were loaded in tension (F) to failure using a universal testing machine. The σ (F/A) was calculated and data were statistically analyzed using ANOVA and Tukey tests (α=0.05). Fracture surfaces were examined to determine the failure mode.

RXA-SC and PF-PA specimens showed the greatest mean σ values after N (13.9 and 13.0MPa, respectively) and TC (12.9 and 14.8MPa, respectively). SC-treated showed greater mean σ values than PA-treated YZ specimens after W.

Regardless of the cement used, W and TC did not significantly reduce the σ of SC-treated YZ resin bonded to dentin.