Effects of air-abrasion pressure on the resin bond strength to zirconia: a combined cyclic loading and thermocycling aging study

Objectives: To determine the combined effect of fatigue cyclic loading and thermocycling (CLTC) on the shear bond strength (SBS) of a resin cement to zirconia surfaces that were previously air-abraded with aluminum oxide (Al 2 O 3 ) particles at different pressures.Materials and Methods: Seventy-two cuboid zirconia specimens were prepared and randomly assigned to 3 groups according to the air-abrasion pressures (1, 2, and 2.8 bar), and each group was further divided into 2 groups depending on aging parameters (n = 12).Panavia F 2.0 was placed on pre-conditioned zirconia surfaces, and SBS testing was performed either after 24 hours or 10,000 fatigue cycles (cyclic loading) and 5,000 thermocycles.Non-contact profilometry was used to measure surface roughness.Failure modes were evaluated under optical and scanning electron microscopy.The data were analyzed using 2-way analysis of variance and χ 2 tests (α = 0.05).Results: The 2.8 bar group showed significantly higher surface roughness compared to the 1 bar group (p < 0.05).The interaction between pressure and time/cycling was not significant on SBS, and pressure did not have a significant effect either.SBS was significantly higher (p = 0.006) for 24 hours storage compared to CLTC.The 2 bar-CLTC group presented significantly higher percentage of pre-test failure during fatigue compared to the other groups.Mixedfailure mode was more frequent than adhesive failure.Conclusions: CLTC significantly decreased the SBS values regardless of the air-abrasion pressure used.