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Background: This study evaluated the effect of air-particle abrasion with different particle sizes on the surface roughness and phase transformation of yttria-stabilized tetragonal zirconia ceramics (Y-TZP). Methods: Eighty-four Y-TZP discs of 15 mm diameter and 1.0 mm thickness were fabricated. The samples were divided into four groups (n = 21): (1) air-particle abrasion with 30 lm CoJet sand blast coating agent (CoJet, 3M ESPE); (2) 50 lm Al 2 O 3 particles; (3) 110 lm Al 2 O 3 particles; and (4) 250 lm Al 2 O 3 particles. Each group was further divided into three subgroups each (n = 7) and treated for 5 seconds, 15 seconds and 30 seconds. Mean surface roughness was determined using a profilometer. The surfaces were analysed with a scanning electron microscope. XRD analysis was employed and the relative amount of the monoclinic phase was calculated. The results were statistically analysed by two-way analysis of variance (ANOVA, p < 0.05). Results: Air-particle abrasion with 250 lm Al 2 O 3 particles for 30 seconds had the highest surface roughness (p < 0.001) and a significantly higher amount of monoclinic phase compared to air-particle abrasion with 30 lm, 50 lm and 110 lm particles (p < 0.001). Conclusions: Duration and particle size of air-particle abrasion affects the roughness and phase transformation of Y-TZP. Longer treatment times with larger particles may result in degradation of material.

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Curing efficiency of dual-cure resin cement is mainly influenced by the lightness of the shades selected.

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