Bond Strength to Silanized Silica-coated Ti (a Novel Silane System)

Objectives: The aim of this study was to evaluate the performance of a novel silane system and an acrylatesilane adhering dendrimer-based (DD1) experimental resin (DD1-MMA-AAEM-DMAEMA system) to silica-coated titanium substrate. Dendrimer resins have smaller shrinkage than the conventional BisGMA resins. Methods: Commercially pure Ti coupons (20mm x 40mm x 1mm) were silica-coated with CoJet system using silica-coated alumina particles (3M ESPE, Seefeld, Germany). 3-acryloxypropyltrimethoxysilane (APCS, 1.0 vol-%) and a blend of 3-acryloxypropyltrimethoxysilane and 1,2-bis(triethoxysilyl)ethane (BTSE; 1.0 vol-% + 1.0 vol-%) were prepared in 95 vol-% ethanol. Fresh silane solution hydrolysis (1 hour) was monitored by Fourier transformation infrared spectroscopy (FTIR). As the control, a fresh, pre-activated dental silane ESPE® Sil (contains 1-2% 3-methacryloyloxypropyltrimethoxysilane, MPS) was used. The silanes were applied onto silica-coated titanium surfaces and allowed to dry for 5 min to form a siloxane film interface. A dendrimer-based resin (with 12 methacrylate groups per DD1 molecule) stubs were photo-polymerized for 40 seconds on silanized Ti samples. The stub specimens (n=10/group) were then thermo-cycled (5-55˚C, 6000 cycles). Shear bond strength (SBS) was measured at a crosshead speed of 1mm/min. The surface examination was made with a scanning electron microscope.

Results: Statistical analysis (ANOVA) showed that silane significantly affects the SBS (p<0.001). All silanes were hydrolyzed (activated) according to the FTIR spectroscopy. Shear bond strengths: ACPS 4.1MPA (SD 0.9 MPA), ACPS+BTSE 5.2 (1.3), and ESPE Sil (MPS) 2.1 (1.6)

Conclusion: A novel silane system (ACPS + BTSE) and ACPS alone gave significantly more durable bonding than a commercial pre-hydorolyzed MPS silane. Other silanes than MPS might yield a higher hydrolytic stability of the siloxane film between dental materials in clinical conditions.