Evaluation of five silane coupling agents on resin-titanium adhesion

Aim: The objective of this laboratory study was to evaluate the adhesion strength of 5 commercially available dental silane coupling agents (ESPE Sil (TM), Bis-silane (TM), Clearfil (TM) Ceramic Primer, VITASIL (R) and Cimara (R)) bonded with an experimental bis-GMA resin to silica-coated titanium. Materials and methods: The silanes were applied onto tribochemically silica-coated planar titanium surfaces followed by addition of experimental bis-GMA resin stubs. The specimens (n = 10) were subjected to 3 different conditions: 1) dry storage for 24 h (baseline), 2) thermo-cycling interval (6000 cycles, 5-55 degrees C) and 3) storage in de-ionized water at 37 degrees C for 6 months respectively. Adhesion strengths of the resin to titanium were measured by using a universal testing machine. Surface examination was made with a scanning electron microscope (SEM) after the adhesion strength test. Data were analyzed with 2-way ANOVA with the Tukey's post hoc analysis (alpha = 0.05). Results: The highest adhesion strength was obtained with VITASIL (R) stored in dry condition (22.8 +/- 1.2 MPa), and the lowest value was obtained with Clearfil (TM) Ceramic Primer in thermo-cycling condition (2.2 +/- 0.6 MPa). The type of storage condition significantly affected the adhesion strength in the following order: dry storage > water storage > thermo-cycling (P < 0.05) but no significant differences in adhesion strength were found among the 5 commercial silanes in same storage conditions (P = 0.06). Mixed (53%) and interfacial (37%) failures were more common than cohesive ones (10%). Conclusion: Storage condition significantly affected the adhesion strength but the evaluated 5 dental silane coupling agents provided similar and clinical acceptable adhesion between resin and silica-coated titanium.