Airborne-Particle Abrasion vs. Hydrofluoric Acid Etching of Dental Ceramics: Impact on the Tensile Bond Strength

This study evaluated whether airborne-particle abrasion could be an alternative to hydrofluoric acid etching as a pretreatment for the adhesive bonding of silicate ceramic restorations. Feldspar (FEL; n = 100), lithium silicate (LiSi; n = 100), and zirconia (ZrO2; (n = 80) substrates were CAD/CAM-fabricated and airborne-particle-abraded with Al2O3 (25 mu m or 50 mu m of mean particle size) at pressures of 0.05 or 0.1 MPa. The controls included FEL (60 s) and LiSi (20 s) etched with hydrofluoric acid. The surface free energy (SFE) and roughness (Ra) were measured. For the tensile bond strength (TBS), surfaces were conditioned using a primer (Monobond Plus) and luted to a resin composite (Variolink Esthetic). TBS was assessed initially (24 h, 37 degrees C water storage) and after thermocycling (5/55 degrees C, 10,000x). Statistical analysis (SPSS, V29) was performed using a one-way ANOVA, post hoc Scheff & eacute;, and a two-group t-test (p = 0.05). Abrasion with 50 mu m and 0.1 MPa induced the highest Ra values across the materials (62.5 +/- 3.88 mu m). ZrO2 exhibited a higher TBS (35.4-49.5 MPa) than FEL and LiSi. For aged LiSi, the specimens treated at 0.1 MPa showed a higher TBS (18.7 +/- 9.0 MPa) than those treated at 0.05 MPa, regardless of the particle size. The etched and aged FEL showed a higher SFE but a lower TBS compared to abrasion. Al2O3 particle abrasion (25 or 50 mu m at 0.1 MPa) may replace etching for silicate-based ceramics, while 50 mu m is recommended for ZrO2 at either pressure.