The effect of different bonding techniques on ceramic/ resin shear bond strength.

PURPOSE: To investigate the effect of different adhesives on the shear bond strength between a feldspathic machinable ceramic and a luting resin. MATERIALS AND METHODS: Seven groups of 20 ceramic specimens each were machined from Vita Mark II blocs. Their surfaces were uniformly treated with 1000-grit paper. Group 1 (control) was hydrofluoric-acid etched for 60 s, group 2 abraded with CoJet, and group 3 PyrosilPen-treated and silanized. Groups 4 and 5 were hydrofluoric-acid etched for 60 s and silanized with two experimental silanes. Variolink II was used as the luting resin for groups 1 to 5. Group 6 and 7 were phosphoric-acid etched for 15 s. Then group 6 was treated with Nexus and group 7 with the Panavia F 2.0 system. All specimens were stored dry for 24 h at 37 degrees C. Shear bond strength was measured prior to and after 5000 thermocycles (TC) between 5 degrees C and 55 degrees C in water. ANOVA was performed with p < or = 0.05. RESULTS: Shear bond strength values 24 h / TC in MPa (SD) were as follows: group 1: 11 (3.0)/ 12 (5.3), group 2: 22 (3.9) / 25 (7.3), group 3: 26 (9.0) / 30 (8.0), group 4: 12 (5.9) / 8 (2.0), group 5: 8 (2.4) / 7 (3.4), group 6: 16 (6.1) / 3 (1.6) and group 7: 16 (8.6) / 16 (4.3). Cojet (24 h, p < or = 0.0007 / TC, p < or = 0.0001) and PyrosilPen (24 h, p < or = 0.0001/ TC, p < or = 0.0001) showed significantly higher bond strength than the control but did not differ significantly from each other. No significant differences between the control and groups 4, 5, 6, and 7 were found. PyrosilPen (p < or = 0.0001) significantly performed best prior to and after TC. Bond strength of experimental silane A (p < or = 0.0499) and Nexus (p < or = 0.0002) significantly decreased after TC. CONCLUSION: Silicoating technology and tribochemistry are fast, trouble-free, and effective surface treatment methods for achieving very good bond strength between feldspathic ceramics and luting resins. Etching with H2F2 can thus be avoided.