Microshear Bond Strength of Resin Bonding Systems to Machinable Ceramic with Different Surface Treatments

Purpose: The bond strength and bond durability of two high-viscosity dual-curing resin luting agents with different surface treatments of ceramic were investigated. Materials and Methods: GN-I machinable ceramic surfaces were treated with 37% phosphoric acid for 30 s (PA), 5% hydrofluoric acid for 5 s (HF-5), 10 s (HF-10), or 30 s (HF-30), or blasting with 50-µm Al2O3 for 10 s (AB). The roughness of the ceramic surface was measured. Treated ceramic surfaces were bonded with three resin bonding systems (RBS): Ceramic Primer/LinkmaxHV (CP/LMHV), Monobond S/VariolinkIIHV (MBS/VLIIHV), or MBS/Heliobond/VLIIHV (MBS/HB/VLIIHV). A microshear test was used to measure the bond strength after 24 h (TC 0) and subsequent thermocycling (TC 10,000 at 4°C and 60°C). ANOVA was performed for statistical analysis, with significance set at p 0.05. Results: For three RBSs, bond strength at TC 0 was not affected, regardless of ceramic surface treatment (p > 0.05). All combined groups of ceramic surface treatment and resin bonding system decreased after 10,000 thermal cycles, especially groups treated with alumina blasting and bonded with each of three RBSs (p 0.05). MBS/HB/VLIIHV with each surface treatment did not improve the bond strength and durability compared with MBS/VLIIHV. Conclusion: CP/LMHV and MBS/VLIIHV obtained sufficient bond strength and bond durability to GN-I machinable ceramic by only cleaning with PA; the application of HB may not be necessary. Keywords: resin luting agent, machinable ceramic, surface treatment, silane coupling agent, microshear bond strength