Effect of post-silanization drying on the bond strength of composite to ceramic

The temperature reported for thermally treating silanated ceramics to improve composite-ceramic bonding is often too high for chairside applications. This study investigated whether post-silanization drying with a stream of warm air could enhance the composite/ceramic tensile bond. Thirty-two ceramic blocks (6 × 6 × 9 mm), 16 of each ceramic, were fabricated and divided into 8 subgroups using 4 roughening procedures and 2 silanization protocols per ceramic (Eris and IPS Empress). Roughening included polishing to 1200 grit as control (P), airborne-particle abrasion (A), hydrofluoric acid etching (E), or a combination of abrasion and etching (AE). Silanated surfaces were dried with room-temperature air (SR) or 45±5°C warm air (SH). An adhesive (Heliobond) was applied and light-polymerized before adding composite (Tetric Ceram). Thirty-three specimens (0.9 × 0.9 × 18 mm) were cut from a pair of blocks and stored in 37°C distilled-water for 3 weeks. Each specimen was loaded under tension until failure in a universal testing machine (n=33). Strength (MPa) was calculated by dividing the failure load by the cross-sectional area. Mode of failure was investigated with scanning electron microscopy (SEM). Statistical analyses were performed with ANOVA and the Tukey HSD test (α=.05). The mean tensile bond strength values (SD) in MPa for P, A, E, and AE procedures were, respectively, 11.4 (5.4), 11.9 (5.4), 9.9 (2.6), and 15.8 (4.3) for Eris/SR; 17.8 (6.2), 20.4 (7.1), 18.0 (6.7), and 18.8 (3.9) for Eris/SH; 9.3 (2.8), 14.0 (4.0) 17.1 (3.7), and 23.2 (6.8) for IPS-Empress/SR; and 14.8 (4.5) 22.6 (4.8), 22.7 (5.0), and 28.7 (4.4) for IPS Empress/SH. ANOVA indicated the influence of ceramic material, roughening, and postsilanization drying was significant ( P