Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
810896 | Journal of the Mechanical Behavior of Biomedical Materials | 2013 | 10 Pages |
This study evaluated the effect of air-particle abrasion protocols on the biaxial flexural strength, surface characteristics and phase transformation of zirconia after cyclic loading. Disc-shaped zirconia specimens (Ø: 15 mm, thickness: 1.2 mm) (N=32) were submitted to one of the air-particle abrasion protocols (n=8 per group): (a) 50 μm Al2O3 particles, (b) 110 μm Al2O3 particles coated with silica (Rocatec Plus), (c) 30 μm Al2O3 particles coated with silica (CoJet Sand) for 20 s at 2.8 bar pressure. Control group received no air-abrasion. All specimens were initially cyclic loaded (×20,000, 50 N, 1 Hz) in water at 37 °C and then subjected to biaxial flexural strength testing where the conditioned surface was under tension. Zirconia surfaces were characterized and roughness was measured with 3D surface profilometer. Phase transformation from tetragonal to monoclinic was determined by Raman spectroscopy. The relative amount of transformed monoclinic zirconia (FM) and transformed zone depth (TZD) were measured using XRD. The data (MPa) were analyzed using ANOVA, Tukey's tests and Weibull modulus (m) were calculated for each group (95% CI). The biaxial flexural strength (MPa) of CoJet treated group (1266.3±158A) was not significantly different than that of Rocatec Plus group (1179±216.4A,B) but was significantly higher than the other groups (Control: 942.3±74.6C; 50 μm Al2O3: 915.2±185.7B,C). Weibull modulus was higher for control (m=13.79) than those of other groups (m=4.95, m=5.64, m=9.13 for group a, b and c, respectively). Surface roughness (Ra) was the highest with 50 μm Al2O3 (0.261 μm) than those of other groups (0.15–0.195 μm). After all air-abrasion protocols, FM increased (15.02%–19.25%) compared to control group (11.12%). TZD also showed increase after air-abrasion protocols (0.83–1.07 μm) compared to control group (0.59 μm). Air-abrasion protocols increased the roughness and monoclinic phase but in turn abrasion with 30 μm Al2O3 particles coated with silica has increased the biaxial flexural strength of the tested zirconia.
► Air-abrasion with alumina or silica increased monoclinic phase of zirconia. ► Deposition of 30 μm silica particles increased flexural strength of zirconia. ► Weilbul modulus after deposition of 30 μm silica particles was the closest to control group.