Journal of Adhesion Science and Technology, Vol.30, No.2, 186-193, 2016
Could readily silanized silica particles substitute silica coating and silanization in conditioning zirconium dioxide for resin adhesion?
This study investigated the effect of particle types with different morphology and surface properties on the wettability and adhesion of resin cement to zirconia. Zirconia specimens (5 x 5 x 1 mm(3)) were wet polished. Specimens were randomly assigned to one of the following protocols (N = 36, n = 9 per group): Group CON: Control, no surface conditioning; Group AL: Chairside air-abrasion with aluminium trioxide (50 mu m Al2O3) + silane; Group SIL: Chairside air-abrasion with alumina particles coated with silica (SIL) (30 mu m SiO2, SilJet) + air-drying + silane; Group 4: Chairside air-abrasion with readily silanized silica particles (SILP) (30 mu m SiO2, SilJet Plus). Adhesive resin was applied and resin cement (Variolink II, Ivoclar) was bonded using polyethylene moulds and photo-polymerized and aged (thermocycling, 6.000 cycles, 5-55 degrees C). Shear bond test was performed using Universal Testing Machine (1 mm/min). Pretest failures were considered 0 MPa. Contact angle measurements were performed (n = 2/group, sessile drop with water). Data (MPa) were analyzed (ANOVA, Tukey's (alpha = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0), values were calculated. Contact angle measurements were in descending order as follows: SIL (74 degrees)(c) < CON (60 degrees)(c) < AL (51 degrees)(b) < SILP (40 degrees)(a). Bond strength (MPa) with SIL (17.2 +/- 4)(a) and SILP (17.3 +/- 1.9)(a) demonstrated no significant difference (p > 0.05), being higher than AL (8.4 +/- 1.5)(b) and CON (0)(c) (p < 0.05). Failure types were exclusively adhesive in all groups. Weibull distribution presented the highest shape (0) for SILP (10.8). SILP presented better wettability than AL. SILP provided similar bond strength to SIL. Readily silanized silica particles may substitute for conventional silica coating and silanization.
Keywords:Adhesion;air-abrasion;bond strength;resin cement;repair;silane coupling agent;surface conditioning;zirconia