Effect of potassium hydrogen difluoride in zirconia-to-resin bonding

The objective of this study was to compare potassium hydrogen difluoride (KHF2) etching for zirconia with commonly used surface roughening and chemical bonding methods (silane, MDP-monomer primer) for resin-based luting cement bonding to zirconia. Zirconia specimens were divided into six groups (n=10) according to surface treatment and bonding procedures, with and without thermocycling (6,000 cycles, 5–55ºC): 1) air-borne particle abrasion with alumina+MDP-monomer (ABP), 2) air-borne particle abrasion with silica-coated trialuminium trioxide+silane (ABPR-S) and 3) KHF2 etching+silane (ETC). Surface roughness and bond strength (SBS-test) for dry and thermocycled specimens were measured. SBS did not vary statistically between the dry groups, but thermocycling decreased the bond strengths of all the tested methods (p