Effect of sandblasting on shear bond strength between heat cured acrylic resin and addition silicone impression material

INTRODUCTION. Surface treatment may influence bonding between acrylic custom trays and addition silicone impression materials. PURPOSE. To evaluate the effect of alumina particle size on shear bond strength and PMMA surface characteristics. MATERIALS AND METHODS. Thirty specimens were assigned to untreated control, 50 µm or 90 µm alumina sandblasting groups ( n = 10) for bond testing. Another 30 specimens were used for roughness testing. Three additional specimens underwent SEM and EDX analysis. Tray adhesive was applied before bonding to addition silicone. RESULTS. The 90 µm group had the highest shear bond strength (0.47 ± 0.25 MPa) and surface roughness (3.85 ± 0.79 µm). Bond strength differed across groups ( F = 9.41; p = 0.0015). The 50 µm group did not differ significantly from control. Aluminum weight fractions were 32.14% and 20.36% after 50 µm and 90 µm treatment, respectively. CONCLUSION. Under the tested laboratory conditions, 90 µm alumina sandblasting with adhesive produced higher bond strength than 50 µm treatment or the untreated control.